str.replace() for substitution in Pandas - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does str.replace() do in pandas?

str.replace() substitutes parts of strings in a pandas Series or DataFrame column with another string.

beginner

How do you replace all occurrences of 'cat' with 'dog' in a pandas Series named pets?

pets.str.replace('cat', 'dog')

intermediate

What parameter do you use in str.replace() to treat the pattern as a regular expression?

The regex parameter. By default, it is True, meaning the pattern is treated as a regex.

intermediate

How can you replace only the first occurrence of a pattern in each string using str.replace()?

Use the n=1 parameter to limit replacement to the first match.

intermediate

What happens if you set regex=False in str.replace()?

The pattern is treated as a literal string, not a regular expression.

What is the default behavior of the pattern parameter in str.replace()?

A It replaces only the first occurrence

B It treats the pattern as a literal string

C It ignores the pattern

D It treats the pattern as a regular expression

By default, str.replace() treats the pattern as a regular expression unless regex=False is set.

How do you replace all occurrences of 'apple' with 'orange' in a pandas Series fruits?

A fruits.replace('apple', 'orange')

B fruits.str.sub('apple', 'orange')

C fruits.str.replace('apple', 'orange')

D fruits.str.change('apple', 'orange')

str.replace() is used to substitute strings inside pandas Series.

Which parameter limits the number of replacements in str.replace()?

A limit

B n

C count

D max

The n parameter controls how many replacements to make.

If you want to replace the literal string '.' (dot), what should you do?

A Escape the dot or set <code>regex=False</code>

B Use <code>case=False</code>

C Use <code>n=0</code>

D Use <code>regex=True</code>

Dot is a special regex character, so escape it or set regex=False to treat it literally.

What type of object does str.replace() return when used on a pandas Series?

A A pandas Series

B A numpy array

C A list

D A string

It returns a new pandas Series with the replacements applied.

Explain how to use str.replace() in pandas to substitute text in a Series. Include how to handle regular expressions and limit replacements.

Think about how you change words in a list of sentences.

Describe a real-life example where str.replace() in pandas can help clean data.

Imagine fixing a messy list of names or addresses.