String Methods
Built-in methods to transform and inspect strings.
Syntax
text.upper()
text.strip()
text.replace(a, b)Strings come with many built-in methods. A few essentials:
upper()/lower()— change case.strip()— remove whitespace from both ends.replace(a, b)— swap text.split(sep)— break a string into a list.startswith()/endswith()— test the ends.
Example
text = ' Python '
print(text.strip())
print(text.strip().upper())
print('cat'.replace('c', 'b'))
print('a,b,c'.split(','))
# Output:
# Python
# PYTHON
# bat
# ['a', 'b', 'c']When to use it
- A registration form strips leading/trailing whitespace from a submitted email before saving it.
- A search feature converts user input to lowercase before comparing it to stored values.
- A CSV processor splits each row string on commas to get a list of individual field values.
More examples
strip, lower, and replace
Chains strip(), lower(), and replace() to normalise a string in one expression.
raw = ' Hello, World! '
clean = raw.strip().lower().replace('world', 'python')
print(clean)
# Output:
# hello, python!split and join
Splits a CSV row into a list with split() then reassembles it with a different separator.
csv_row = 'Alice,30,Engineer'
fields = csv_row.split(',')
print(fields) # ['Alice', '30', 'Engineer']
rejoined = ' | '.join(fields)
print(rejoined) # Alice | 30 | Engineerstartswith, endswith, find
Uses endswith(), startswith(), and find() to inspect and locate substrings.
filename = 'report_2024.pdf'
print(filename.endswith('.pdf')) # True
print(filename.startswith('rep')) # True
idx = filename.find('2024')
print(idx) # 7
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