String methods on Series in Data Analysis Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Series in pandas?

A Series is a one-dimensional labeled array in pandas that can hold any data type, like numbers or strings. Think of it like a list with labels for each item.

beginner

How do you access string methods on a pandas Series?

You use the .str accessor before the string method. For example, series.str.lower() converts all strings in the Series to lowercase.

beginner

What does series.str.contains('abc') do?

It checks each string in the Series to see if it contains the substring 'abc'. It returns a Series of True or False values.

intermediate

How can you handle missing values when using string methods on a Series?

Most string methods on Series automatically skip missing values (NaN). You can also use na='' or na=False in some methods to control behavior.

beginner

Give an example of using series.str.replace().

If you have a Series with strings and want to replace 'cat' with 'dog', you can use series.str.replace('cat', 'dog'). This changes all 'cat' words to 'dog' in the Series.

Which pandas accessor allows you to use string methods on a Series?

A .s

B .str

C .text

D .string

The correct accessor for string methods on a Series is .str.

What does series.str.upper() do?

A Removes uppercase letters from strings

B Checks if strings contain uppercase letters

C Converts all strings in the Series to uppercase

D Splits strings at uppercase letters

series.str.upper() converts all strings in the Series to uppercase.

If a Series has missing values (NaN), what happens when you use series.str.len()?

A Returns NaN for missing values

B Raises an error

C Ignores missing values and returns length for others

D Replaces missing values with zero

String methods return NaN for missing values by default.

How do you check if strings in a Series start with 'data'?

A series.str.startswith('data')

B series.str.contains('data')

C series.str.find('data')

D series.str.match('data')

series.str.startswith('data') checks if strings start with 'data'.

What does series.str.split(',') return?

A A single string with commas removed

B An error because split is not supported

C A boolean Series if commas exist

D A Series of lists splitting strings at commas

series.str.split(',') splits each string at commas and returns a Series of lists.

Explain how to use string methods on a pandas Series and give two examples.

Think about how you call string functions on each item in the Series.

Describe how missing values are handled when applying string methods on a Series.

Consider what happens if a string method meets a NaN value.