str.strip() / str.lstrip() / str.rstrip()

# Removes whitespace or specified characters from both ends of a string.
str.strip(chars=None)

# Removes only from the beginning (left end) of a string.
str.lstrip(chars=None)

# Removes only from the end (right end) of a string.
str.rstrip(chars=None)

strip_basic.py

text = "   Hello, Python!   "
print(text.strip())
print(len(text))
print(len(text.strip()))

line = "\t\n  data  \n\t"
print(repr(line.strip()))

path = "///usr/local/bin"
print(path.lstrip("/"))

number_str = "000042"
print(number_str.lstrip("0"))

filename = "report.txt..."
print(filename.rstrip("."))

line_with_newline = "data row\n"
clean_line = line_with_newline.rstrip("\n")
print(repr(clean_line))

Running the code produces the following output:

python3 strip_basic.py
Hello, Python!
20
14
'data'
usr/local/bin
42
report.txt
'data row'

strip_chars.py

print("aaabbccXYZccbba".strip("abc"))
print("hello".strip("helo"))

Running the code produces the following output:

python3 strip_chars.py
XYZ

strip_csv.py

csv_line = "  Kiryu Kazuma  , 27  , Former Yakuza  "
fields = [field.strip() for field in csv_line.split(",")]
print(fields)

members = ["  Nishikiyama Akira  ", "  Majima Goro  ", "  Sawamura Haruka  ", "  Kashiwagi Osamu  "]
cleaned = [m.strip() for m in members]
print(cleaned)

url = "https://example.com"
domain = url.removeprefix("https://")
print(domain)

filename2 = "report.txt"
name = filename2.removesuffix(".txt")
print(name)

Running the code produces the following output:

python3 strip_csv.py
['Kiryu Kazuma', '27', 'Former Yakuza']
['Nishikiyama Akira', 'Majima Goro', 'Sawamura Haruka', 'Kashiwagi Osamu']
example.com
report

Common Mistake 1: strip() removes a set of characters, not a substring

The chars argument of strip() is treated as a set of characters to remove, not as a substring. For example, strip("Kiryu") removes any of the individual characters K, i, r, y, u from the ends — not the string "Kiryu" as a whole. Use removeprefix() or removesuffix() (Python 3.9+) to remove a prefix or suffix as a unit.

mistake1_ng.py

name = "Kiryu Kazuma"
result = name.strip("Kiryu")
print(result)

Running the code produces the following output:

python3 mistake1_ng.py
 Kazuma

Instead of removing "Kiryu" as a whole prefix, strip() removes the individual characters K, i, r, y, u from both ends. The space before "Kazuma" is not in the set, so removal stops there.

mistake1_ok.py

name = "Kiryu Kazuma"
result = name.removeprefix("Kiryu ")
print(result)

Running the code produces the following output:

python3 mistake1_ok.py
Kazuma

Common Mistake 2: strip() cannot remove whitespace in the middle

strip() only removes characters from the start and end of a string. To remove extra whitespace in the middle, combine split() and join().

mistake2_ng.py

text = "Kiryu  Kazuma  is  strong"
print(text.strip())

Running the code produces the following output:

python3 mistake2_ng.py
Kiryu  Kazuma  is  strong

mistake2_ok.py

text = "Kiryu  Kazuma  is  strong"
normalized = " ".join(text.split())
print(normalized)

Running the code produces the following output:

python3 mistake2_ok.py
Kiryu Kazuma is strong

The chars argument of strip() is treated as a set of characters to remove, not as a substring. For example, "abc".strip("ab") does not remove the sequence "ab" as a unit — it removes any a or b characters that appear at either end. To remove a prefix or suffix as a whole unit, use removeprefix() or removesuffix() (Python 3.9+).

All of these methods return a new string. The original string is not modified. When reading a file line by line, rstrip("\n") or rstrip() is commonly used to remove the trailing newline from each line.

For data cleaning that combines stripping with splitting, see also str.split(). For searching within strings, see str.find() / str.index().