How to Use findall in Python: Syntax and Examples

Use re.findall(pattern, string) to find all non-overlapping matches of pattern in string. It returns a list of all matches found as strings or tuples if groups are used.

Syntax

The re.findall() function has this syntax:

• pattern: The regular expression pattern to search for.
• string: The text where you want to find matches.
• Returns a list of all matches found in the string.

python

import re
matches = re.findall(pattern, string)

Example

This example finds all words that start with a capital letter in a sentence.

python

import re
text = "Hello World! This is a Test."
matches = re.findall(r"\b[A-Z][a-z]*\b", text)
print(matches)

Output

['Hello', 'World', 'This', 'Test']

Common Pitfalls

One common mistake is using re.findall() with groups in the pattern, which returns tuples instead of strings. Also, forgetting to import re causes errors.

Another pitfall is expecting overlapping matches, but findall only finds non-overlapping matches.

python

import re
text = "abc123def456"
# Wrong: pattern with groups returns tuples
matches_wrong = re.findall(r"(\d)(\d)(\d)", text)
print(matches_wrong)

# Right: pattern without groups returns strings
matches_right = re.findall(r"\d{3}", text)
print(matches_right)

Output

[('1', '2', '3'), ('4', '5', '6')]
['123', '456']

Quick Reference

• re.findall(pattern, string): Returns all matches as a list.
• Use raw strings (prefix r) for patterns to avoid escape issues.
• Groups in pattern return tuples of groups per match.
• Matches are non-overlapping.

Key Takeaways

Use re.findall() to get all matches of a pattern in a string as a list.

Patterns with groups return tuples for each match; without groups, they return strings.

Always import the re module before using findall.

Use raw strings (r"pattern") to write regex patterns safely.

findall finds non-overlapping matches only.