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--- python_wiki:list_comprehensions [2018/08/03 00:58]
billdozor [The Code]
+++ python_wiki:list_comprehensions [2019/05/25 23:50]
@@ Line 1: / Line 1: @@
-====== List Comprehensions ======
-**General Information**
-List comprehensions are a way to create lists based on lists.
-They cut out a step in which you would create an intermediate list just to create a new list.
-**Checklist**
-  * Python 2 or 3
-----
-====== Usage ======
-FIXME -> Fill out list comprehension example and code.
-Using the code snippet.
-<code bash>
-chmod +x list-comp.py
-./list-comp.py
-# Example output
-('The tuple is: ', ('centos', 'ubuntu', 'fedora', 'windows', 'arch', 'freebsd'))
-('The nix os list is: ', ['centos', 'ubuntu', 'fedora', 'arch', 'freebsd'])
-</code>
-----
-====== The Code ======
-**List Comprehension Syntax**
-<code python>
-new_list = [x for x in iterable if filter]
-</code>
-\\
-**List Comprehension Example**
-<code python list-comp.py>
-#!/usr/bin/python
-# Tuple with a list of OS's
-my_tuple = ('centos', 'ubuntu', 'fedora', 'windows', 'arch', 'freebsd')
-# Create a new list based off of the tuple, exclude 'windows'
-nix_os = [entry for entry in my_tuple if entry != 'windows']
-print("The tuple is: ", my_tuple)
-print("The nix os list is: ", nix_os)
-</code>
-\\
-The long way **without list comprehensions** of the above code is
-<code python>
-#!/usr/bin/python
-# Tuple with a list of OS's
-my_tuple = ('centos', 'ubuntu', 'fedora', 'windows', 'arch', 'freebsd')
-# Create a new list based off of the tuple, exclude 'windows'
-# This time, do not use a list comprehension
-nix_os = []
-for entry in my_tuple:
-  if entry != 'windows':
-    nix_os.append(entry)
-print("The tuple is: ", my_tuple)
-print("The nix os list is: ", nix_os)
-</code>
-----