LANGUAGE » PYTHON

String

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Reference:docs.python.org

Operators ​

python
'Hello ' + 'world!'  # String concatenation.
u'こんにちは'       # String with unicode characters.

Methods ​

Methods are called on the string, like text.method().

MethodDescription
lower()Return a lowercased copy of the string.
upper()Return a uppercased copy of the string.
isalpha()Return True if it only has letters.
isdigit()Return True if it only has numbers.
isalnum()Return True if it has letters or numbers.
startswith('prefix')Return True if string starts with the prefix, otherwise return False.
endswith('prefix')Return True if string ends with the suffix, otherwise return False.
replace('pattern', repl, count=0)Return a replaced copy of the string. (For regex use re package).
split(' ')Return a list splitted by a delimiter string.
splitlines()Return a list splitted by line breaks.
join(iterable)Return a string which is the concatenation of the strings in iterable.
strip(' ')Return a copy of the string with the leading and trailing characters removed.
rstrip(' ')Return a copy of the string with the trailing characters removed.
lstrip(' ')Return a copy of the string with the leading characters removed.
decode('utf-8')Return a string decoded using the given encoding.

Functions ​

These are builtin keywords, the string must be passed as a parameter.

FunctionDescription
lenReturn the number of characters in the string.
ordReturn an integer representing the Unicode code point of that character.

F-string ​

External documentation

New in version 3.6.

A formatted string literal or f-string is a string literal that is prefixed with f or F.

python
name = 'John'
f'My name is {name}.'

To escape { or }, double it:

python
number = 727
f'Number is {{ {number} }}'  # Out: 'Number is { 727 }'

Format ​

Array-like usage:

python
'{}{}{}'.format(a, b, c)
'{0}{1}{2}'.format(a, b, c)

Dictionary-like usage:

python
'{name}'.format(name='John')

Numbers formatting:

python
'{:03d}'.format(8)       # '008'
'{:,d}'.format(1234567)  # '1,234,567'
'{:+.4f}'.format(3.141592653589793)  # '+3.1416'
'{:-.4f}'.format(3.141592653589793)  # '3.1416' (default)
'{: .4f}'.format(3.141592653589793)  # ' 3.1416'
'{:.2%}'.format(0.2548)  # '25.48%'

Date formatting:

python
'{:%Y/%m/%d %H:%M:%S}'.format(datetime.now())

Content alignment:

python
'{:<10}'.format('left')    # 'left      '
'{:^10}'.format('center')  # '  center  '
'{:>10}'.format('right')   # '     right'
'{:_^10}'.format('fill')   # '___fill___'

Docstring ​