CME193: IntroductiontoScientificPython Lecture3: Tuples ...

CME 193: Introduction to Scientific Python Lecture 3: Tuples, sets, dictionaries and strings

Sven Schmit

stanford.edu/~schmit/cme193

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Tuples Dictionaries Sets Strings Modules Exercises

Contents

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Tuples

Seemingly similar to lists

>>> myTuple = (1, 2, 3) >>> myTuple[1] 2 >>> myTuple[1:3] (2, 3)

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Tuples are immutable

Unlike lists, we cannot change elements.

>>> myTuple = ([1, 2], [2, 3]) >>> myTuple[0] = [3,4] Traceback (most recent call last):

File "", line 1, in TypeError: 'tuple' object does not support item assignment >>> myTuple[0][1] = 3 >>> myTuple ([1, 3], [2, 3])

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Packing and unpacking

t = 1, 2, 3 x, y, z = t print t # (1, 2, 3) print y # 2

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