Coding 101

May 15th 2014

Coding 101 17

Python: Tuples

We review outputting lists, go deeper with sorting, then it's tuples time!

Although the show is no longer in production, you can enjoy episodes from the TWiT Archives.
Guests: Dale Chase
Category: Help & How To

Welcome to Coding 101 - It's the TWiT show that gives YOU the knowledge to live in the wonderful world of the programmer. This week we are introducing our newest module, Python with Code Warrior Dale Chase!

To see all the code used in today's episode, go to Our Github Repository for Module 2

Printing Everything within a List:

The way we've been printing lists is to use a "for loop" to print everything within the list:

podcasters = ['Leo','Lisa','Padre', 'Snubs', 'Bryan', 'OMGchad']

for entries in range (0,6):

- print podcasters[entries]

  • This will print each individual entry on its own line.

If we JUST wanted to know the contents of the list:

mylist = [142, 512, 'dog', 'cat', 'bird', 123]

print mylist

  • This will print EVERYTHING that is in the list "mylist" - including the comas, spaces and brackets

Sorting the List

  • We've been using "destructive sorting" with the "list.sort()" function
  • When we use "sort()" on a list, we sort "IN PLACE" which destroys the original list

SortMe = [1, 23, 6, 4, 99]

for entries in range (0,5):

- print SortMe[entries]

raw_input ("Press Enter")

SortMe.sort();

for entries in range (0,5):

- print SortMe[entries]

NON-DESTRUCTIVE SORTING

  • We can do a non-destructive sorting of a list.
  • It keep the original list while sorting the data.

podcasters = ['Leo','Lisa','Padre', 'Snubs', 'Bryan', 'OMGchad', 1234]

print podcasters

print "Woot, let's sort!"

sortedpodcasters = sorted(podcasters)

raw_input("Press Enter to Continue")

print podcasters

print sortedpodcasters

  • We can ALSO sort WITHOUT creating a new list

podcasters = ['Leo','Lisa','Padre', 'Snubs', 'Bryan', 'OMGchad', 1234]

print sorted(podcasters)

Tuples

  • Tuples work like lists, but they are immutable. They cannot be changed.
  • They use parentheses instead of brackets
  • You can have a list of tuples.

twit_tuples = [

('Padre', 'TWiET', 72),

('Snubs', 'C101', 22),

('Bryan', 'KnowHow', 6),

]

print twit_tuples

Sorting Tuples

twit_tuples = [

('Padre', 'TWiET', 72),

('Snubs', 'C101', 22),

('Bryan', 'KnowHow', 6),

]

print sorted(twit_tuples, key=lambda twit: twit[2])

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