Lists in Python

Introduction to Python for Finance

Adina Howe

Instructor

Lists - square brackets [ ]

months = ['January', 'February', 'March', 'April', 'May', 'June']
Introduction to Python for Finance

Python is zero-indexed

list_figure

Introduction to Python for Finance

Subset lists

months = ['January', 'February', 'March', 'April', 'May', 'June']

months[0]

'January'

months[2]

'March'
Introduction to Python for Finance

Negative indexing of lists

months = ['January', 'February', 'March', 'April', 'May', 'June']

months[-1]

'June'

months[-2]

'May'
Introduction to Python for Finance

Subsetting multiple list elements with slicing

Slicing syntax

# Includes the start and up to (but not including) the end
mylist[startAt:endBefore]

Example

months = ['January', 'February', 'March', 'April', 'May', 'June']

months[2:5]

['March', 'April', 'May']

months[-4:-1]

['March', 'April', 'May']
Introduction to Python for Finance

Extended slicing with lists

months = ['January', 'February', 'March', 'April', 'May', 'June']

months[3:]

['April', 'May', 'June']

months[:3]

['January', 'February', 'March']
Introduction to Python for Finance

Slicing with Steps

# Includes the start and up to (but not including) the end
mylist[startAt:endBefore:step] 

months = ['January', 'February', 'March', 'April', 'May', 'June']

months[0:6:2]

['January', 'March', 'May']

months[0:6:3]

['January', 'April']
Introduction to Python for Finance

Let's practice!

Introduction to Python for Finance

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