str.strip()

Added in v3.x · Updated March 13, 2026 · String Methods

stdlib string strip

The .strip() method removes leading and trailing characters from a string. By default, it removes all whitespace characters—spaces, tabs, newlines, carriage returns, and form feeds. This makes it essential for cleaning user input, processing file contents, and parsing data from external sources.

Signature

str.strip([chars])

Parameters

Parameter	Type	Default	Description
`chars`	`str`	`None`	A string specifying the set of characters to remove. If `None`, all whitespace characters are removed.

Return Value

Returns a new string with the specified characters removed from both the beginning and end. The original string remains unchanged since strings are immutable in Python.

Examples

Basic Usage

>>> "  hello  ".strip()
'hello'

>>> "\t\nhello\n\t".strip()
'hello'

>>> "   \n\n   multiple\nlines   \n".strip()
'multiple\nlines'

The default behavior handles common whitespace scenarios. It removes spaces at the start and end, along with any newline or tab characters.

Stripping Specific Characters

>>> "xxhelloxx".strip('x')
'hello'

>>> "---hello---".strip('-')
'hello'

>>> "xyxyhelloxyxy".strip('xy')
'hello'

>>> "***hello***".strip('*')
'hello'

>>> "<<<>>>data<<<>>>".strip('<>')
'data'

When you provide the chars argument, .strip() removes any combination of those characters from both ends. It keeps stripping until it encounters a character not in the set.

Stripping Multiple Character Types

>>> "##!!@@data@@!!##".strip('#!@')
'data'

>>> " \t-=--hello--=-\t ".strip(' \t-=')
'hello'

This is useful when dealing with formatted strings that have consistent prefixes or suffixes.

Practical Use Cases

Cleaning user input:

username = input("Enter username: ").strip()
email = input("Enter email: ").strip()

# Without strip(), users might accidentally add spaces
# that cause login failures or inconsistent data

Reading file lines:

with open("data.txt") as f:
    for line in f:
        line = line.strip()
        if line:  # Skip empty lines
            process(line)

# Note: file.readlines() keeps the newline character
# strip() removes it for clean processing

Parsing CSV or delimited data:

>>> "  42  ".strip()
'42'

>>> "   3.14   ".strip()
'3.14'

>>> "\tpassword\t".strip()
'password'

Handling API responses:

response = api.get("/user")
name = response.json()["name"].strip()  # Clean any accidental whitespace

Behavior Details

How It Works

The method scans from the beginning of the string, removing characters that appear in the chars set. Once it hits a character not in the set, it stops. Then it repeats the process from the end of the string.

>>> "aaabaaaa".strip('a')
'ba'  # Leading 'a's removed, stops at 'b'
         # Trailing 'a's removed, stops at 'a'

>>> "aaabbaaaa".strip('a')
'bb'  # Leading 'a's removed, stops at 'b'
         # Trailing 'a's removed, stops at 'b'

Character Order Doesn’t Matter

>>> "hello---".strip('-')
'hello'

>>> "hello---".strip('---')
'hello'

>>> "hello---".strip('--')
'hello'

# All equivalent when removing the same characters

Empty String Returns Empty

>>> "".strip()
''

>>> "   ".strip()
''

Performance

.strip() is implemented in C and runs in O(n) time where n is the number of characters removed. For most use cases involving short strings or whitespace removal, the performance is negligible. The method creates a new string, so memory usage scales with the input size.

Common Mistakes

Assuming it removes from the middle of the string:

>>> "hello world".strip()
'hello world'  # Space in middle is NOT removed

# For middle spaces, use replace():
>>> "hello world".replace(" ", "")
'helloworld'

Forgetting it returns a new string:

s = "  hello  "
s.strip()              # This returns a new string but doesn't modify s
s = s.strip()          # Assign the result to keep it

Confusing with JavaScript’s trim():

# Python: strip() is the equivalent of JavaScript's trim()
# Both remove leading/trailing whitespace