# SOME DESCRIPTIVE TITLE.

# Copyright (C) 2001-2025, Python Software Foundation

# This file is distributed under the same license as the Python package.

# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.

#

# Translators:

# Rafael Fontenelle <[email protected]>, 2025

#

#, fuzzy

msgid ""

msgstr ""

"Project-Id-Version: Python 3.12\n"

"Report-Msgid-Bugs-To: \n"

"POT-Creation-Date: 2025-07-25 16:03+0000\n"

"PO-Revision-Date: 2025-07-18 19:59+0000\n"

"Last-Translator: Rafael Fontenelle <[email protected]>, 2025\n"

"Language-Team: Chinese (China) (https://app.transifex.com/python-doc/teams/5390/zh_CN/)\n"

"MIME-Version: 1.0\n"

"Content-Type: text/plain; charset=UTF-8\n"

"Content-Transfer-Encoding: 8bit\n"

"Language: zh_CN\n"

"Plural-Forms: nplurals=1; plural=0;\n"

#: ../../tutorial/datastructures.rst:5

msgid "Data Structures"

msgstr "数据结构"

#: ../../tutorial/datastructures.rst:7

msgid ""

"This chapter describes some things you've learned about already in more "

"detail, and adds some new things as well."

msgstr "本章深入讲解之前学过的一些内容，同时，还增加了新的知识点。"

#: ../../tutorial/datastructures.rst:13

msgid "More on Lists"

msgstr "列表详解"

#: ../../tutorial/datastructures.rst:15

msgid ""

"The list data type has some more methods. Here are all of the methods of "

"list objects:"

msgstr "列表数据类型支持很多方法，列表对象的所有方法所示如下："

#: ../../tutorial/datastructures.rst:22

msgid "Add an item to the end of the list. Similar to ``a[len(a):] = [x]``."

msgstr "在列表末尾添加一项。 类似于 ``a[len(a):] = [x]``。"

#: ../../tutorial/datastructures.rst:28

msgid ""

"Extend the list by appending all the items from the iterable. Similar to "

"``a[len(a):] = iterable``."

msgstr "通过添加来自 iterable 的所有项来扩展列表。 类似于 ``a[len(a):] = iterable``。"

#: ../../tutorial/datastructures.rst:35

msgid ""

"Insert an item at a given position. The first argument is the index of the "

"element before which to insert, so ``a.insert(0, x)`` inserts at the front "

"of the list, and ``a.insert(len(a), x)`` is equivalent to ``a.append(x)``."

msgstr ""

"在指定位置插入元素。第一个参数是插入元素的索引，因此，``a.insert(0, x)`` 在列表开头插入元素， ``a.insert(len(a), "

"x)`` 等同于 ``a.append(x)`` 。"

#: ../../tutorial/datastructures.rst:43

msgid ""

"Remove the first item from the list whose value is equal to *x*. It raises "

"a :exc:`ValueError` if there is no such item."

msgstr "从列表中删除第一个值为 *x* 的元素。未找到指定元素时，触发 :exc:`ValueError` 异常。"

#: ../../tutorial/datastructures.rst:50

msgid ""

"Remove the item at the given position in the list, and return it. If no "

"index is specified, ``a.pop()`` removes and returns the last item in the "

"list. It raises an :exc:`IndexError` if the list is empty or the index is "

"outside the list range."

msgstr ""

"移除列表中给定位置上的条目，并返回该条目。 如果未指定索引号，则 ``a.pop()`` 将移除并返回列表中的最后一个条目。 "

"如果列表为空或索引号在列表索引范围之外则会引发 :exc:`IndexError`。"

#: ../../tutorial/datastructures.rst:59

msgid "Remove all items from the list. Similar to ``del a[:]``."

msgstr "移除列表中的所有项。 类似于 ``del a[:]``。"

#: ../../tutorial/datastructures.rst:65

msgid ""

"Return zero-based index in the list of the first item whose value is equal "

"to *x*. Raises a :exc:`ValueError` if there is no such item."

msgstr "返回列表中第一个值为 *x* 的元素的零基索引。未找到指定元素时，触发 :exc:`ValueError` 异常。"

#: ../../tutorial/datastructures.rst:68

msgid ""

"The optional arguments *start* and *end* are interpreted as in the slice "

"notation and are used to limit the search to a particular subsequence of the"

" list. The returned index is computed relative to the beginning of the full"

" sequence rather than the *start* argument."

msgstr ""

"可选参数 *start* 和 *end* 是切片符号，用于将搜索限制为列表的特定子序列。返回的索引是相对于整个序列的开始计算的，而不是 *start* "

"参数。"

#: ../../tutorial/datastructures.rst:77

msgid "Return the number of times *x* appears in the list."

msgstr "返回列表中元素 *x* 出现的次数。"

#: ../../tutorial/datastructures.rst:83

msgid ""

"Sort the items of the list in place (the arguments can be used for sort "

"customization, see :func:`sorted` for their explanation)."

msgstr "就地排序列表中的元素（要了解自定义排序参数，详见 :func:`sorted`）。"

#: ../../tutorial/datastructures.rst:90

msgid "Reverse the elements of the list in place."

msgstr "翻转列表中的元素。"

#: ../../tutorial/datastructures.rst:96

msgid "Return a shallow copy of the list. Similar to ``a[:]``."

msgstr "返回列表的浅拷贝。 类似于 ``a[:]``。"

#: ../../tutorial/datastructures.rst:99

msgid "An example that uses most of the list methods::"

msgstr "多数列表方法示例："

#: ../../tutorial/datastructures.rst:101

msgid ""

">>> fruits = ['orange', 'apple', 'pear', 'banana', 'kiwi', 'apple', 'banana']\n"

">>> fruits.count('apple')\n"

"2\n"

">>> fruits.count('tangerine')\n"

"0\n"

">>> fruits.index('banana')\n"

"3\n"

">>> fruits.index('banana', 4) # Find next banana starting at position 4\n"

"6\n"

">>> fruits.reverse()\n"

">>> fruits\n"

"['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange']\n"

">>> fruits.append('grape')\n"

">>> fruits\n"

"['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange', 'grape']\n"

">>> fruits.sort()\n"

">>> fruits\n"

"['apple', 'apple', 'banana', 'banana', 'grape', 'kiwi', 'orange', 'pear']\n"

">>> fruits.pop()\n"

"'pear'"

msgstr ""

">>> fruits = ['orange', 'apple', 'pear', 'banana', 'kiwi', 'apple', 'banana']\n"

">>> fruits.count('apple')\n"

"2\n"

">>> fruits.count('tangerine')\n"

"0\n"

">>> fruits.index('banana')\n"

"3\n"

">>> fruits.index('banana', 4) # 从 4 号位开始查找下一个 banana\n"

"6\n"

">>> fruits.reverse()\n"

">>> fruits\n"

"['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange']\n"

">>> fruits.append('grape')\n"

">>> fruits\n"

"['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange', 'grape']\n"

">>> fruits.sort()\n"

">>> fruits\n"

"['apple', 'apple', 'banana', 'banana', 'grape', 'kiwi', 'orange', 'pear']\n"

">>> fruits.pop()\n"

"'pear'"

#: ../../tutorial/datastructures.rst:122

msgid ""

"You might have noticed that methods like ``insert``, ``remove`` or ``sort`` "

"that only modify the list have no return value printed -- they return the "

"default ``None``. [#]_ This is a design principle for all mutable data "

"structures in Python."

msgstr ""

"你可能已经注意到 ``insert``, ``remove`` 或 ``sort`` 等仅修改列表的方法都不会打印返回值 -- 它们返回默认值 "

"``None``。 [#]_ 这是适用于 Python 中所有可变数据结构的设计原则。"

#: ../../tutorial/datastructures.rst:127

msgid ""

"Another thing you might notice is that not all data can be sorted or "

"compared. For instance, ``[None, 'hello', 10]`` doesn't sort because "

"integers can't be compared to strings and ``None`` can't be compared to "

"other types. Also, there are some types that don't have a defined ordering "

"relation. For example, ``3+4j < 5+7j`` isn't a valid comparison."

msgstr ""

"你可能会注意到的另一件事是并非所有数据都可以排序或比较。 举例来说，``[None, 'hello', 10]`` 就不可排序因为整数不能与字符串比较而"

" ``None`` 不能与其他类型比较。 此外，还存在一些没有定义顺序关系的类型。 例如，``3+4j < 5+7j`` 就不是一个合法的比较。"

#: ../../tutorial/datastructures.rst:138

msgid "Using Lists as Stacks"

msgstr "用列表实现堆栈"

#: ../../tutorial/datastructures.rst:143

msgid ""

"The list methods make it very easy to use a list as a stack, where the last "

"element added is the first element retrieved (\"last-in, first-out\"). To "

"add an item to the top of the stack, use :meth:`!append`. To retrieve an "

"item from the top of the stack, use :meth:`!pop` without an explicit index."

" For example::"

msgstr ""

"列表方法使得将列表用作栈非常容易，最后添加的元素会最先被取出（“后进先出”）。 要将一个条目添加到栈顶，可使用 :meth:`!append`。 "

"要从栈顶取出一个条目，则使用 :meth:`!pop` 且不必显式指定索引。 例如::"

#: ../../tutorial/datastructures.rst:148

msgid ""

">>> stack = [3, 4, 5]\n"

">>> stack.append(6)\n"

">>> stack.append(7)\n"

">>> stack\n"

"[3, 4, 5, 6, 7]\n"

">>> stack.pop()\n"

"7\n"

">>> stack\n"

"[3, 4, 5, 6]\n"

">>> stack.pop()\n"

"6\n"

">>> stack.pop()\n"

"5\n"

">>> stack\n"

"[3, 4]"

msgstr ""

">>> stack = [3, 4, 5]\n"

">>> stack.append(6)\n"

">>> stack.append(7)\n"

">>> stack\n"

"[3, 4, 5, 6, 7]\n"

">>> stack.pop()\n"

"7\n"

">>> stack\n"

"[3, 4, 5, 6]\n"

">>> stack.pop()\n"

"6\n"

">>> stack.pop()\n"

"5\n"

">>> stack\n"

"[3, 4]"

#: ../../tutorial/datastructures.rst:168

msgid "Using Lists as Queues"

msgstr "用列表实现队列"

#: ../../tutorial/datastructures.rst:172

msgid ""

"It is also possible to use a list as a queue, where the first element added "

"is the first element retrieved (\"first-in, first-out\"); however, lists are"

" not efficient for this purpose. While appends and pops from the end of "

"list are fast, doing inserts or pops from the beginning of a list is slow "

"(because all of the other elements have to be shifted by one)."

msgstr ""

"列表也可以用作队列，最先加入的元素，最先取出（“先进先出”）；然而，列表作为队列的效率很低。因为，在列表末尾添加和删除元素非常快，但在列表开头插入或移除元素却很慢（因为所有其他元素都必须移动一位）。"

#: ../../tutorial/datastructures.rst:178

msgid ""

"To implement a queue, use :class:`collections.deque` which was designed to "

"have fast appends and pops from both ends. For example::"

msgstr "实现队列最好用 :class:`collections.deque`，可以快速从两端添加或删除元素。例如："

#: ../../tutorial/datastructures.rst:181

msgid ""

">>> from collections import deque\n"

">>> queue = deque([\"Eric\", \"John\", \"Michael\"])\n"

">>> queue.append(\"Terry\") # Terry arrives\n"

">>> queue.append(\"Graham\") # Graham arrives\n"

">>> queue.popleft() # The first to arrive now leaves\n"

"'Eric'\n"

">>> queue.popleft() # The second to arrive now leaves\n"

"'John'\n"

">>> queue # Remaining queue in order of arrival\n"

"deque(['Michael', 'Terry', 'Graham'])"

msgstr ""

">>> from collections import deque\n"

">>> queue = deque([\"Eric\", \"John\", \"Michael\"])\n"

">>> queue.append(\"Terry\") # Terry 到了\n"

">>> queue.append(\"Graham\") # Graham 到了\n"

">>> queue.popleft() # 第一个到的现在走了\n"

"'Eric'\n"

">>> queue.popleft() # 第二个到的现在走了\n"

"'John'\n"

">>> queue # 按到达顺序排列的剩余队列\n"

"deque(['Michael', 'Terry', 'Graham'])"

#: ../../tutorial/datastructures.rst:196

msgid "List Comprehensions"

msgstr "列表推导式"

#: ../../tutorial/datastructures.rst:198

msgid ""

"List comprehensions provide a concise way to create lists. Common "

"applications are to make new lists where each element is the result of some "

"operations applied to each member of another sequence or iterable, or to "

"create a subsequence of those elements that satisfy a certain condition."

msgstr ""

"列表推导式创建列表的方式更简洁。常见的用法为，对序列或可迭代对象中的每个元素应用某种操作，用生成的结果创建新的列表；或用满足特定条件的元素创建子序列。"

#: ../../tutorial/datastructures.rst:203

msgid "For example, assume we want to create a list of squares, like::"

msgstr "例如，创建平方值的列表："

#: ../../tutorial/datastructures.rst:205

msgid ""

">>> squares = []\n"

">>> for x in range(10):\n"

"... squares.append(x**2)\n"

"...\n"

">>> squares\n"

"[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]"

msgstr ""

">>> squares = []\n"

">>> for x in range(10):\n"

"... squares.append(x**2)\n"

"...\n"

">>> squares\n"

"[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]"

#: ../../tutorial/datastructures.rst:212

msgid ""

"Note that this creates (or overwrites) a variable named ``x`` that still "

"exists after the loop completes. We can calculate the list of squares "

"without any side effects using::"

msgstr "注意，这段代码创建（或覆盖）变量 ``x``，该变量在循环结束后仍然存在。下述方法可以无副作用地计算平方列表："

#: ../../tutorial/datastructures.rst:216

msgid "squares = list(map(lambda x: x**2, range(10)))"

msgstr "squares = list(map(lambda x: x**2, range(10)))"

#: ../../tutorial/datastructures.rst:218

msgid "or, equivalently::"

msgstr "或等价于："

#: ../../tutorial/datastructures.rst:220

msgid "squares = [x**2 for x in range(10)]"

msgstr "squares = [x**2 for x in range(10)]"

#: ../../tutorial/datastructures.rst:222

msgid "which is more concise and readable."

msgstr "上面这种写法更简洁、易读。"

#: ../../tutorial/datastructures.rst:224

msgid ""

"A list comprehension consists of brackets containing an expression followed "

"by a :keyword:`!for` clause, then zero or more :keyword:`!for` or "

":keyword:`!if` clauses. The result will be a new list resulting from "

"evaluating the expression in the context of the :keyword:`!for` and "

":keyword:`!if` clauses which follow it. For example, this listcomp combines "

"the elements of two lists if they are not equal::"

msgstr ""

"列表推导式的方括号内包含以下内容：一个表达式，后面为一个 :keyword:`!for` 子句，然后，是零个或多个 :keyword:`!for` 或 "

":keyword:`!if` 子句。结果是由表达式依据 :keyword:`!for` 和 :keyword:`!if` 子句求值计算而得出一个新列表。"

" 举例来说，以下列表推导式将两个列表中不相等的元素组合起来："

#: ../../tutorial/datastructures.rst:231

msgid ""

">>> [(x, y) for x in [1,2,3] for y in [3,1,4] if x != y]\n"

"[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]"

msgstr ""

">>> [(x, y) for x in [1,2,3] for y in [3,1,4] if x != y]\n"

"[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]"

#: ../../tutorial/datastructures.rst:234

msgid "and it's equivalent to::"

msgstr "等价于："

#: ../../tutorial/datastructures.rst:236

msgid ""

">>> combs = []\n"

">>> for x in [1,2,3]:\n"

"... for y in [3,1,4]:\n"

"... if x != y:\n"

"... combs.append((x, y))\n"

"...\n"

">>> combs\n"

"[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]"

msgstr ""

">>> combs = []\n"

">>> for x in [1,2,3]:\n"

"... for y in [3,1,4]:\n"

"... if x != y:\n"

"... combs.append((x, y))\n"

"...\n"

">>> combs\n"

"[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]"

#: ../../tutorial/datastructures.rst:245

msgid ""

"Note how the order of the :keyword:`for` and :keyword:`if` statements is the"

" same in both these snippets."

msgstr "注意，上面两段代码中，:keyword:`for` 和 :keyword:`if` 的顺序相同。"

#: ../../tutorial/datastructures.rst:248

msgid ""

"If the expression is a tuple (e.g. the ``(x, y)`` in the previous example), "

"it must be parenthesized. ::"

msgstr "表达式是元组（例如上例的 ``(x, y)``）时，必须加上括号："

#: ../../tutorial/datastructures.rst:251

msgid ""

">>> vec = [-4, -2, 0, 2, 4]\n"

">>> # create a new list with the values doubled\n"

">>> [x*2 for x in vec]\n"

"[-8, -4, 0, 4, 8]\n"

">>> # filter the list to exclude negative numbers\n"

">>> [x for x in vec if x >= 0]\n"

"[0, 2, 4]\n"

">>> # apply a function to all the elements\n"

">>> [abs(x) for x in vec]\n"

"[4, 2, 0, 2, 4]\n"

">>> # call a method on each element\n"

">>> freshfruit = [' banana', ' loganberry ', 'passion fruit ']\n"

">>> [weapon.strip() for weapon in freshfruit]\n"

"['banana', 'loganberry', 'passion fruit']\n"

">>> # create a list of 2-tuples like (number, square)\n"

">>> [(x, x**2) for x in range(6)]\n"

"[(0, 0), (1, 1), (2, 4), (3, 9), (4, 16), (5, 25)]\n"

">>> # the tuple must be parenthesized, otherwise an error is raised\n"

">>> [x, x**2 for x in range(6)]\n"

" File \"<stdin>\", line 1\n"

" [x, x**2 for x in range(6)]\n"

" ^^^^^^^\n"

"SyntaxError: did you forget parentheses around the comprehension target?\n"

">>> # flatten a list using a listcomp with two 'for'\n"

">>> vec = [[1,2,3], [4,5,6], [7,8,9]]\n"

">>> [num for elem in vec for num in elem]\n"

"[1, 2, 3, 4, 5, 6, 7, 8, 9]"

msgstr ""

">>> vec = [-4, -2, 0, 2, 4]\n"

">>> # 新建一个将值翻倍的列表\n"

">>> [x*2 for x in vec]\n"

"[-8, -4, 0, 4, 8]\n"

">>> # 过滤列表以排除负数\n"

">>> [x for x in vec if x >= 0]\n"

"[0, 2, 4]\n"

">>> # 对所有元素应用一个函数\n"

">>> [abs(x) for x in vec]\n"

"[4, 2, 0, 2, 4]\n"

">>> # 在每个元素上调用一个方法\n"

">>> freshfruit = [' banana', ' loganberry ', 'passion fruit ']\n"

">>> [weapon.strip() for weapon in freshfruit]\n"

"['banana', 'loganberry', 'passion fruit']\n"

">>> # 创建一个包含 (数字, 平方) 2 元组的列表\n"

">>> [(x, x**2) for x in range(6)]\n"

"[(0, 0), (1, 1), (2, 4), (3, 9), (4, 16), (5, 25)]\n"

">>> # 元组必须加圆括号，否则会引发错误\n"

">>> [x, x**2 for x in range(6)]\n"

" File \"<stdin>\", line 1\n"

" [x, x**2 for x in range(6)]\n"

" ^^^^^^^\n"

"SyntaxError: did you forget parentheses around the comprehension target?\n"

">>> # 使用两个 'for' 来展平嵌套的列表\n"

">>> vec = [[1,2,3], [4,5,6], [7,8,9]]\n"

">>> [num for elem in vec for num in elem]\n"

"[1, 2, 3, 4, 5, 6, 7, 8, 9]"

#: ../../tutorial/datastructures.rst:279

msgid ""

"List comprehensions can contain complex expressions and nested functions::"

msgstr "列表推导式可以使用复杂的表达式和嵌套函数："

#: ../../tutorial/datastructures.rst:281

msgid ""

">>> from math import pi\n"

">>> [str(round(pi, i)) for i in range(1, 6)]\n"

"['3.1', '3.14', '3.142', '3.1416', '3.14159']"

msgstr ""

">>> from math import pi\n"

">>> [str(round(pi, i)) for i in range(1, 6)]\n"

"['3.1', '3.14', '3.142', '3.1416', '3.14159']"

#: ../../tutorial/datastructures.rst:286

msgid "Nested List Comprehensions"

msgstr "嵌套的列表推导式"

#: ../../tutorial/datastructures.rst:288

msgid ""

"The initial expression in a list comprehension can be any arbitrary "

"expression, including another list comprehension."

msgstr "列表推导式中的初始表达式可以是任何表达式，甚至可以是另一个列表推导式。"

#: ../../tutorial/datastructures.rst:291

msgid ""

"Consider the following example of a 3x4 matrix implemented as a list of 3 "

"lists of length 4::"

msgstr "下面这个 3x4 矩阵，由 3 个长度为 4 的列表组成："

#: ../../tutorial/datastructures.rst:294

msgid ""

">>> matrix = [\n"

"... [1, 2, 3, 4],\n"

"... [5, 6, 7, 8],\n"

"... [9, 10, 11, 12],\n"

"... ]"

msgstr ""

">>> matrix = [\n"

"... [1, 2, 3, 4],\n"

"... [5, 6, 7, 8],\n"

"... [9, 10, 11, 12],\n"

"... ]"

#: ../../tutorial/datastructures.rst:300

msgid "The following list comprehension will transpose rows and columns::"

msgstr "下面的列表推导式可以转置行列："

#: ../../tutorial/datastructures.rst:302

msgid ""

">>> [[row[i] for row in matrix] for i in range(4)]\n"

"[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]"

msgstr ""

">>> [[row[i] for row in matrix] for i in range(4)]\n"

"[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]"

#: ../../tutorial/datastructures.rst:305

msgid ""

"As we saw in the previous section, the inner list comprehension is evaluated"

" in the context of the :keyword:`for` that follows it, so this example is "

"equivalent to::"

msgstr "如我们在之前小节中看到的，内部的列表推导式是在它之后的 :keyword:`for` 的上下文中被求值的，所以这个例子等价于::"

#: ../../tutorial/datastructures.rst:309

msgid ""

">>> transposed = []\n"

">>> for i in range(4):\n"

"... transposed.append([row[i] for row in matrix])\n"

"...\n"

">>> transposed\n"

"[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]"

msgstr ""

">>> transposed = []\n"

">>> for i in range(4):\n"

"... transposed.append([row[i] for row in matrix])\n"

"...\n"

">>> transposed\n"

"[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]"

#: ../../tutorial/datastructures.rst:316

msgid "which, in turn, is the same as::"

msgstr "反过来说，也等价于："

#: ../../tutorial/datastructures.rst:318

msgid ""

">>> transposed = []\n"

">>> for i in range(4):\n"

"... # the following 3 lines implement the nested listcomp\n"

"... transposed_row = []\n"

"... for row in matrix:\n"

"... transposed_row.append(row[i])\n"

"... transposed.append(transposed_row)\n"

"...\n"

">>> transposed\n"

"[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]"

msgstr ""

">>> transposed = []\n"

">>> for i in range(4):\n"

"... # 以下 3 行实现了嵌套的列表组\n"

"... transposed_row = []\n"

"... for row in matrix:\n"

"... transposed_row.append(row[i])\n"

"... transposed.append(transposed_row)\n"

"...\n"

">>> transposed\n"

"[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]"

#: ../../tutorial/datastructures.rst:329

msgid ""

"In the real world, you should prefer built-in functions to complex flow "

"statements. The :func:`zip` function would do a great job for this use "

"case::"

msgstr "实际应用中，最好用内置函数替代复杂的流程语句。此时，:func:`zip` 函数更好用："

#: ../../tutorial/datastructures.rst:332

msgid ""

">>> list(zip(*matrix))\n"

"[(1, 5, 9), (2, 6, 10), (3, 7, 11), (4, 8, 12)]"

msgstr ""

">>> list(zip(*matrix))\n"

"[(1, 5, 9), (2, 6, 10), (3, 7, 11), (4, 8, 12)]"

#: ../../tutorial/datastructures.rst:335

msgid ""

"See :ref:`tut-unpacking-arguments` for details on the asterisk in this line."

msgstr "关于本行中星号的详细说明，参见 :ref:`tut-unpacking-arguments`。"

#: ../../tutorial/datastructures.rst:340

msgid "The :keyword:`!del` statement"

msgstr ":keyword:`!del` 语句"

#: ../../tutorial/datastructures.rst:342

msgid ""

"There is a way to remove an item from a list given its index instead of its "

"value: the :keyword:`del` statement. This differs from the :meth:`!pop` "

"method which returns a value. The :keyword:`!del` statement can also be "

"used to remove slices from a list or clear the entire list (which we did "

"earlier by assignment of an empty list to the slice). For example::"

msgstr ""

"可以按索引而不是按值从一个列表移除条目：即使用 :keyword:`del` 语句。 这不同于返回一个值的 :meth:`!pop` 方法。 "

":keyword:`!del` 语句还可被用来从列表移除切片或清空整个列表（之前我们通过将一个空列表赋值给切片实现此功能）。 例如::"

#: ../../tutorial/datastructures.rst:348

msgid ""

">>> a = [-1, 1, 66.25, 333, 333, 1234.5]\n"

">>> del a[0]\n"

">>> a\n"

"[1, 66.25, 333, 333, 1234.5]\n"

">>> del a[2:4]\n"

">>> a\n"

"[1, 66.25, 1234.5]\n"

">>> del a[:]\n"

">>> a\n"

"[]"

msgstr ""

">>> a = [-1, 1, 66.25, 333, 333, 1234.5]\n"

">>> del a[0]\n"

">>> a\n"

"[1, 66.25, 333, 333, 1234.5]\n"

">>> del a[2:4]\n"

">>> a\n"

"[1, 66.25, 1234.5]\n"

">>> del a[:]\n"

">>> a\n"

"[]"

#: ../../tutorial/datastructures.rst:359

msgid ":keyword:`del` can also be used to delete entire variables::"

msgstr ":keyword:`del` 也可以用来删除整个变量："

#: ../../tutorial/datastructures.rst:361

msgid ">>> del a"

msgstr ">>> del a"

#: ../../tutorial/datastructures.rst:363

msgid ""

"Referencing the name ``a`` hereafter is an error (at least until another "

"value is assigned to it). We'll find other uses for :keyword:`del` later."

msgstr "此后，再引用 ``a`` 就会报错（直到为它赋与另一个值）。后文会介绍 :keyword:`del` 的其他用法。"

#: ../../tutorial/datastructures.rst:370

msgid "Tuples and Sequences"

msgstr "元组和序列"

#: ../../tutorial/datastructures.rst:372

msgid ""

"We saw that lists and strings have many common properties, such as indexing "

"and slicing operations. They are two examples of *sequence* data types (see"

" :ref:`typesseq`). Since Python is an evolving language, other sequence "

"data types may be added. There is also another standard sequence data type:"

" the *tuple*."

msgstr ""

"列表和字符串有很多共性，例如，索引和切片操作。这两种数据类型是 *序列* （参见 :ref:`typesseq`）。随着 Python "

"语言的发展，其他的序列类型也被加入其中。本节介绍另一种标准序列类型：*元组*。"

#: ../../tutorial/datastructures.rst:378

msgid ""

"A tuple consists of a number of values separated by commas, for instance::"

msgstr "元组由多个用逗号隔开的值组成，例如："

#: ../../tutorial/datastructures.rst:380

msgid ""

">>> t = 12345, 54321, 'hello!'\n"

">>> t[0]\n"

"12345\n"

">>> t\n"

"(12345, 54321, 'hello!')\n"

">>> # Tuples may be nested:\n"

">>> u = t, (1, 2, 3, 4, 5)\n"

">>> u\n"

"((12345, 54321, 'hello!'), (1, 2, 3, 4, 5))\n"

">>> # Tuples are immutable:\n"

">>> t[0] = 88888\n"

"Traceback (most recent call last):\n"

" File \"<stdin>\", line 1, in <module>\n"

"TypeError: 'tuple' object does not support item assignment\n"

">>> # but they can contain mutable objects:\n"

">>> v = ([1, 2, 3], [3, 2, 1])\n"

">>> v\n"

"([1, 2, 3], [3, 2, 1])"

msgstr ""

">>> t = 12345, 54321, 'hello!'\n"

">>> t[0]\n"

"12345\n"

">>> t\n"

"(12345, 54321, 'hello!')\n"

">>> # 元组可以嵌套：\n"

">>> u = t, (1, 2, 3, 4, 5)\n"

">>> u\n"

"((12345, 54321, 'hello!'), (1, 2, 3, 4, 5))\n"

">>> # 元组是不可变对象：\n"

">>> t[0] = 88888\n"

"Traceback (most recent call last):\n"

" File \"<stdin>\", line 1, in <module>\n"

"TypeError: 'tuple' object does not support item assignment\n"

">>> # 但它们可以包含可变对象：\n"

">>> v = ([1, 2, 3], [3, 2, 1])\n"

">>> v\n"

"([1, 2, 3], [3, 2, 1])"

#: ../../tutorial/datastructures.rst:400

msgid ""

"As you see, on output tuples are always enclosed in parentheses, so that "

"nested tuples are interpreted correctly; they may be input with or without "

"surrounding parentheses, although often parentheses are necessary anyway (if"

" the tuple is part of a larger expression). It is not possible to assign to"

" the individual items of a tuple, however it is possible to create tuples "

"which contain mutable objects, such as lists."

msgstr ""

"输出时，元组都要由圆括号标注，这样才能正确地解释嵌套元组。输入时，圆括号可有可无，不过经常是必须的（如果元组是更大的表达式的一部分）。不允许为元组中的单个元素赋值，当然，可以创建含列表等可变对象的元组。"

#: ../../tutorial/datastructures.rst:407

msgid ""

"Though tuples may seem similar to lists, they are often used in different "

"situations and for different purposes. Tuples are :term:`immutable`, and "

"usually contain a heterogeneous sequence of elements that are accessed via "

"unpacking (see later in this section) or indexing (or even by attribute in "

"the case of :func:`namedtuples <collections.namedtuple>`). Lists are "

":term:`mutable`, and their elements are usually homogeneous and are accessed"

" by iterating over the list."

msgstr ""

"虽然，元组与列表很像，但使用场景不同，用途也不同。元组是 :term:`immutable` "

"（不可变的），一般可包含异质元素序列，通过解包（见本节下文）或索引访问（如果是 :func:`namedtuples "

"<collections.namedtuple>`，可以属性访问）。列表是 :term:`mutable` "

"（可变的），列表元素一般为同质类型，可迭代访问。"

#: ../../tutorial/datastructures.rst:415

msgid ""

"A special problem is the construction of tuples containing 0 or 1 items: the"

" syntax has some extra quirks to accommodate these. Empty tuples are "

"constructed by an empty pair of parentheses; a tuple with one item is "

"constructed by following a value with a comma (it is not sufficient to "

"enclose a single value in parentheses). Ugly, but effective. For example::"

msgstr ""

"构造 0 个或 1 "

"个元素的元组比较特殊：为了适应这种情况，对句法有一些额外的改变。用一对空圆括号就可以创建空元组；只有一个元素的元组可以通过在这个元素后添加逗号来构建（圆括号里只有一个值的话不够明确）。丑陋，但是有效。例如："

#: ../../tutorial/datastructures.rst:421

msgid ""

">>> empty = ()\n"

">>> singleton = 'hello', # <-- note trailing comma\n"

">>> len(empty)\n"

"0\n"

">>> len(singleton)\n"

"1\n"

">>> singleton\n"

"('hello',)"

msgstr ""

">>> empty = ()\n"

">>> singleton = 'hello', # <-- 注意末尾的逗号\n"

">>> len(empty)\n"

"0\n"

">>> len(singleton)\n"

"1\n"

">>> singleton\n"

"('hello',)"

#: ../../tutorial/datastructures.rst:430

msgid ""

"The statement ``t = 12345, 54321, 'hello!'`` is an example of *tuple "

"packing*: the values ``12345``, ``54321`` and ``'hello!'`` are packed "

"together in a tuple. The reverse operation is also possible::"

msgstr ""

"语句 ``t = 12345, 54321, 'hello!'`` 是 *元组打包* 的例子：值 ``12345``, ``54321`` 和 "

"``'hello!'`` 一起被打包进元组。逆操作也可以："

#: ../../tutorial/datastructures.rst:434

msgid ">>> x, y, z = t"

msgstr ">>> x, y, z = t"

#: ../../tutorial/datastructures.rst:436

msgid ""

"This is called, appropriately enough, *sequence unpacking* and works for any"

" sequence on the right-hand side. Sequence unpacking requires that there "

"are as many variables on the left side of the equals sign as there are "

"elements in the sequence. Note that multiple assignment is really just a "

"combination of tuple packing and sequence unpacking."

msgstr ""

"称之为 *序列解包* "

"也是妥妥的，适用于右侧的任何序列。序列解包时，左侧变量与右侧序列元素的数量应相等。注意，多重赋值其实只是元组打包和序列解包的组合。"

#: ../../tutorial/datastructures.rst:446

msgid "Sets"

msgstr "集合"

#: ../../tutorial/datastructures.rst:448

msgid ""

"Python also includes a data type for *sets*. A set is an unordered "

"collection with no duplicate elements. Basic uses include membership "

"testing and eliminating duplicate entries. Set objects also support "

"mathematical operations like union, intersection, difference, and symmetric "

"difference."

msgstr ""

"Python 还支持 *集合* "

"这种数据类型。集合是由不重复元素组成的无序容器。基本用法包括成员检测、消除重复元素。集合对象支持合集、交集、差集、对称差分等数学运算。"

#: ../../tutorial/datastructures.rst:453

msgid ""

"Curly braces or the :func:`set` function can be used to create sets. Note: "

"to create an empty set you have to use ``set()``, not ``{}``; the latter "

"creates an empty dictionary, a data structure that we discuss in the next "

"section."

msgstr ""

"创建集合用花括号或 :func:`set` 函数。注意，创建空集合只能用 ``set()``，不能用 ``{}``，``{}`` "

"创建的是空字典，下一小节介绍数据结构：字典。"

#: ../../tutorial/datastructures.rst:457

msgid "Here is a brief demonstration::"

msgstr "以下是一些简单的示例 ::"

#: ../../tutorial/datastructures.rst:459

msgid ""

">>> basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}\n"

">>> print(basket) # show that duplicates have been removed\n"

"{'orange', 'banana', 'pear', 'apple'}\n"

">>> 'orange' in basket # fast membership testing\n"

"True\n"

">>> 'crabgrass' in basket\n"

"False\n"

"\n"

">>> # Demonstrate set operations on unique letters from two words\n"

">>>\n"

">>> a = set('abracadabra')\n"

">>> b = set('alacazam')\n"

">>> a # unique letters in a\n"

"{'a', 'r', 'b', 'c', 'd'}\n"

">>> a - b # letters in a but not in b\n"

"{'r', 'd', 'b'}\n"

">>> a | b # letters in a or b or both\n"

"{'a', 'c', 'r', 'd', 'b', 'm', 'z', 'l'}\n"

">>> a & b # letters in both a and b\n"

"{'a', 'c'}\n"

">>> a ^ b # letters in a or b but not both\n"

"{'r', 'd', 'b', 'm', 'z', 'l'}"

msgstr ""

">>> basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}\n"

">>> print(basket) # 显示重复项已被移除\n"

"{'orange', 'banana', 'pear', 'apple'}\n"

">>> 'orange' in basket # 快速成员检测\n"

"True\n"

">>> 'crabgrass' in basket\n"

"False\n"

"\n"

">>> # 演示针对两个单词中独有的字母进行集合运算\n"

">>>\n"

">>> a = set('abracadabra')\n"

">>> b = set('alacazam')\n"

">>> a # a 中独有的字母\n"

"{'a', 'r', 'b', 'c', 'd'}\n"

">>> a - b # 存在于 a 中但不存在于 b 中的字母\n"

"{'r', 'd', 'b'}\n"

">>> a | b # 存在于 a 或 b 中或两者中皆有的字母\n"

"{'a', 'c', 'r', 'd', 'b', 'm', 'z', 'l'}\n"

">>> a & b # 同时存在于 a 和 b 中的字母\n"

"{'a', 'c'}\n"

">>> a ^ b # 存在于 a 或 b 中但非两者中皆有的字母\n"

"{'r', 'd', 'b', 'm', 'z', 'l'}"

#: ../../tutorial/datastructures.rst:482

msgid ""

"Similarly to :ref:`list comprehensions <tut-listcomps>`, set comprehensions "

"are also supported::"

msgstr "与 :ref:`列表推导式 <tut-listcomps>` 类似，集合也支持推导式："

#: ../../tutorial/datastructures.rst:485

msgid ""

">>> a = {x for x in 'abracadabra' if x not in 'abc'}\n"

">>> a\n"

"{'r', 'd'}"

msgstr ""

">>> a = {x for x in 'abracadabra' if x not in 'abc'}\n"

">>> a\n"

"{'r', 'd'}"

#: ../../tutorial/datastructures.rst:493

msgid "Dictionaries"

msgstr "字典"

#: ../../tutorial/datastructures.rst:495

msgid ""

"Another useful data type built into Python is the *dictionary* (see "

":ref:`typesmapping`). Dictionaries are sometimes found in other languages as"

" \"associative memories\" or \"associative arrays\". Unlike sequences, "

"which are indexed by a range of numbers, dictionaries are indexed by *keys*,"

" which can be any immutable type; strings and numbers can always be keys. "

"Tuples can be used as keys if they contain only strings, numbers, or tuples;"

" if a tuple contains any mutable object either directly or indirectly, it "

"cannot be used as a key. You can't use lists as keys, since lists can be "

"modified in place using index assignments, slice assignments, or methods "

"like :meth:`!append` and :meth:`!extend`."

msgstr ""

"另一个常用的 Python 内置数据类型是 *字典* (参见 :ref:`typesmapping`)。 "

"字典在其他编程语言中可能称为“联合内存”或“联合数组”。 与以连续整数为索引的序列不同，字典是以 *键* "

"来索引的，键可以是任何不可变类型；字符串和数字总是可以作为键。 "

"元组在其仅包含字符串、数字或元组时也可以作为键；如果一个元组直接或间接地包含了任何可变对象，则不可以用作键。 "

"你不能使用列表作为键，因为列表可使用索引赋值、切片赋值或 :meth:`!append` 和 :meth:`!extend` 等方法进行原地修改。"

#: ../../tutorial/datastructures.rst:506

msgid ""

"It is best to think of a dictionary as a set of *key: value* pairs, with the"

" requirement that the keys are unique (within one dictionary). A pair of "

"braces creates an empty dictionary: ``{}``. Placing a comma-separated list "

"of key:value pairs within the braces adds initial key:value pairs to the "

"dictionary; this is also the way dictionaries are written on output."

msgstr ""

"可以把字典理解为 *键值对* 的集合，但字典的键必须是唯一的。花括号 ``{}`` "

"用于创建空字典。另一种初始化字典的方式是，在花括号里输入逗号分隔的键值对，这也是字典的输出方式。"

#: ../../tutorial/datastructures.rst:512

msgid ""

"The main operations on a dictionary are storing a value with some key and "

"extracting the value given the key. It is also possible to delete a "

"key:value pair with ``del``. If you store using a key that is already in "

"use, the old value associated with that key is forgotten. It is an error to"

" extract a value using a non-existent key."

msgstr ""

"字典的主要用途是通过关键字存储、提取值。用 ``del`` "

"可以删除键值对。用已存在的关键字存储值，与该关键字关联的旧值会被取代。通过不存在的键提取值，则会报错。"

#: ../../tutorial/datastructures.rst:518

msgid ""

"Performing ``list(d)`` on a dictionary returns a list of all the keys used "

"in the dictionary, in insertion order (if you want it sorted, just use "

"``sorted(d)`` instead). To check whether a single key is in the dictionary, "

"use the :keyword:`in` keyword."

msgstr ""

"对字典执行 ``list(d)`` 操作，返回该字典中所有键的列表，按插入次序排列（如需排序，请使用 "

"``sorted(d)``）。检查字典里是否存在某个键，使用关键字 :keyword:`in`。"

#: ../../tutorial/datastructures.rst:523

msgid "Here is a small example using a dictionary::"

msgstr "以下是一些字典的简单示例："

#: ../../tutorial/datastructures.rst:525

msgid ""

">>> tel = {'jack': 4098, 'sape': 4139}\n"

">>> tel['guido'] = 4127\n"

">>> tel\n"

"{'jack': 4098, 'sape': 4139, 'guido': 4127}\n"

">>> tel['jack']\n"

"4098\n"

">>> del tel['sape']\n"

">>> tel['irv'] = 4127\n"

">>> tel\n"

"{'jack': 4098, 'guido': 4127, 'irv': 4127}\n"

">>> list(tel)\n"

"['jack', 'guido', 'irv']\n"

">>> sorted(tel)\n"

"['guido', 'irv', 'jack']\n"

">>> 'guido' in tel\n"

"True\n"

">>> 'jack' not in tel\n"

"False"

msgstr ""

">>> tel = {'jack': 4098, 'sape': 4139}\n"

">>> tel['guido'] = 4127\n"

">>> tel\n"

"{'jack': 4098, 'sape': 4139, 'guido': 4127}\n"

">>> tel['jack']\n"

"4098\n"

">>> del tel['sape']\n"

">>> tel['irv'] = 4127\n"

">>> tel\n"

"{'jack': 4098, 'guido': 4127, 'irv': 4127}\n"

">>> list(tel)\n"

"['jack', 'guido', 'irv']\n"

">>> sorted(tel)\n"

"['guido', 'irv', 'jack']\n"

">>> 'guido' in tel\n"

"True\n"

">>> 'jack' not in tel\n"

"False"

#: ../../tutorial/datastructures.rst:544

msgid ""

"The :func:`dict` constructor builds dictionaries directly from sequences of "

"key-value pairs::"

msgstr ":func:`dict` 构造函数可以直接用键值对序列创建字典："

#: ../../tutorial/datastructures.rst:547

msgid ""

">>> dict([('sape', 4139), ('guido', 4127), ('jack', 4098)])\n"

"{'sape': 4139, 'guido': 4127, 'jack': 4098}"

msgstr ""

">>> dict([('sape', 4139), ('guido', 4127), ('jack', 4098)])\n"

"{'sape': 4139, 'guido': 4127, 'jack': 4098}"

#: ../../tutorial/datastructures.rst:550

msgid ""

"In addition, dict comprehensions can be used to create dictionaries from "

"arbitrary key and value expressions::"

msgstr "字典推导式可以用任意键值表达式创建字典："

#: ../../tutorial/datastructures.rst:553

msgid ""

">>> {x: x**2 for x in (2, 4, 6)}\n"

"{2: 4, 4: 16, 6: 36}"

msgstr ""

">>> {x: x**2 for x in (2, 4, 6)}\n"

"{2: 4, 4: 16, 6: 36}"

#: ../../tutorial/datastructures.rst:556

msgid ""

"When the keys are simple strings, it is sometimes easier to specify pairs "

"using keyword arguments::"

msgstr "关键字是比较简单的字符串时，直接用关键字参数指定键值对更便捷："

#: ../../tutorial/datastructures.rst:559

msgid ""

">>> dict(sape=4139, guido=4127, jack=4098)\n"