Add comprehension code

returnvalue · returnvalue · commit 42ca53c8a451 · 2020-07-29T14:27:02.000-04:00
diff --git a/README.md b/README.md
@@ -12,4 +12,5 @@ repository breaks up the code into individual .py files, and the full tutorial f
 5. [Python Dictionary Tutorial](https://vegibit.com/python-dictionary-tutorial/)
 6. [Python If Statements](https://vegibit.com/python-if-statements/)
 7. [Python While And For Loops](https://vegibit.com/python-while-and-for-loops/)
-8. [Python Recursion Examples](https://vegibit.com/python-recursion-examples/)
+8. [Python Recursion Examples](https://vegibit.com/python-recursion-examples/)
+9. [Python Comprehension Tutorial](https://vegibit.com/python-comprehension-tutorial/)
diff --git a/comprehension.py b/comprehension.py
@@ -0,0 +1,148 @@
+# Comprehensions in Python provide us with a short and concise way to
+# construct new sequences (such as lists, set, dictionary etc.) using
+# sequences which have been already defined.
+
+# Simple List Comprehension
+# for version
+numbers = [1, 2, 3, 4, 5, 6, 7]
+my_list = []
+for number in numbers:
+    my_list.append(number)
+print(my_list)
+# [1, 2, 3, 4, 5, 6, 7]
+
+# comprehension version
+numbers = [1, 2, 3, 4, 5, 6, 7]
+my_list = [number for number in numbers]
+print(my_list)
+# [1, 2, 3, 4, 5, 6, 7]
+
+
+# Taking An Action On Each Item
+# for version
+numbers = [1, 2, 3, 4, 5, 6, 7]
+my_list = []
+for number in numbers:
+    my_list.append(number * number)
+print(my_list)
+# [1, 4, 9, 16, 25, 36, 49]
+
+# comprehension version
+numbers = [1, 2, 3, 4, 5, 6, 7]
+my_list = [number * number for number in numbers]
+print(my_list)
+# [1, 4, 9, 16, 25, 36, 49]
+
+# lambda version
+numbers = [1, 2, 3, 4, 5, 6, 7]
+my_list = map(lambda number: number * number, numbers)
+print(list(my_list))
+# [1, 4, 9, 16, 25, 36, 49]
+
+
+# Comprehension If
+# for version
+numbers = [1, 2, 3, 4, 5, 6, 7]
+my_list = []
+for number in numbers:
+    if number % 2 == 0:
+        my_list.append(number * number)
+print(my_list)
+# [4, 16, 36]
+
+# comprehension version
+numbers = [1, 2, 3, 4, 5, 6, 7]
+my_list = [number * number for number in numbers if number % 2 == 0]
+print(my_list)
+# [4, 16, 36]
+
+
+# Comprehension If Else
+# for version
+numbers = [1, 2, 3, 4, 5, 6, 7]
+my_list = []
+for number in numbers:
+    if number % 2 == 0:
+        my_list.append(number)
+    else:
+        my_list.append(number * number)
+print(my_list)
+# [1, 2, 9, 4, 25, 6, 49]
+
+# comprehension version
+numbers = [1, 2, 3, 4, 5, 6, 7]
+my_list = [number if number % 2 == 0 else number * number for number in numbers]
+print(my_list)
+# [1, 2, 9, 4, 25, 6, 49]
+
+
+# Comprehension Nested
+# for version
+my_list = []
+for letter in 'abc':
+    for number in range(1, 4):
+        my_list.append((letter, number))
+print(my_list)
+# [('a', 1), ('a', 2), ('a', 3), ('b', 1), ('b', 2), ('b', 3), ('c', 1), ('c', 2), ('c', 3)]
+
+# comprehension version
+my_list = [(letter, number) for letter in 'abc' for number in range(1, 4)]
+print(my_list)
+# [('a', 1), ('a', 2), ('a', 3), ('b', 1), ('b', 2), ('b', 3), ('c', 1), ('c', 2), ('c', 3)]
+
+
+# Comprehensions Dictionary
+# for version
+colors = ['Red', 'Green', 'Orange']
+veggies = ['Pepper', 'Onion', 'Squash']
+
+my_dict = {}
+for color, veggie in zip(colors, veggies):
+    my_dict[color] = veggie
+print(my_dict)
+# {'Red': 'Pepper', 'Green': 'Onion', 'Orange': 'Squash'}
+
+# comprehension version
+colors = ['Red', 'Green', 'Orange']
+veggies = ['Pepper', 'Onion', 'Squash']
+
+my_dict = {color: veggie for color, veggie in zip(colors, veggies)}
+print(my_dict)
+# {'Red': 'Pepper', 'Green': 'Onion', 'Orange': 'Squash'}
+
+
+# Dict Comprehension With If
+# for version
+colors = ['Red', 'Green', 'Orange']
+veggies = ['Pepper', 'Onion', 'Squash']
+
+my_dict = {}
+for color, veggie in zip(colors, veggies):
+    if color != 'Orange':
+        my_dict[color] = veggie
+print(my_dict)
+# {'Red': 'Pepper', 'Green': 'Onion'}
+
+# comprehension version
+colors = ['Red', 'Green', 'Orange']
+veggies = ['Pepper', 'Onion', 'Squash']
+
+my_dict = {color: veggie for color, veggie in zip(colors, veggies) if color != 'Orange'}
+print(my_dict)
+# {'Red': 'Pepper', 'Green': 'Onion'}
+
+
+# Comprehension Set
+# for version
+numbers = [1, 1, 2, 2, 3, 3, 4, 4, 5, 5]
+my_set = set()
+for number in numbers:
+    my_set.add(number)
+print(my_set)
+# {1, 2, 3, 4, 5}
+
+# comprehension version
+numbers = [1, 1, 2, 2, 3, 3, 4, 4, 5, 5]
+my_set = {number for number in numbers}
+print(my_set)
+# {1, 2, 3, 4, 5}
