Strings

A string is an immutable sequence of characters that is treated as a value. Strings support all of the immutable sequence functions and operators that result in a new string. For example, "abcdef"[1:4] results in the output "bcd".

In Python, characters are represented by strings of length one.

Strings literals are defined by the use of single or triple quoting. Strings that are defined using single quotes cannot span lines, while strings that are defined using triple quotes can. A string can be enclosed in single quotes (') or double quotes ("). A quoting character may contain the other quoting character un-escaped or the quoting character escaped, that is preceded by the backslash (\) character.

Examples

"This is a string"
'This is also a string'
"It's a string"
'This book is called "Python Scripting and Automation Guide".'
"This is an escape quote (\") in a quoted string"

Multiple strings separated by white space are automatically concatenated by the Python parser. This makes it easier to enter long strings and to mix quote types in a single string, for example:

"This string uses ' and " 'that string uses ".'

This results in the following output:

This string uses ' and that string uses ".

Strings support several useful methods. Some of these methods are given in the following table.

Table 1. String methods
Method	Usage
`s.capitalize()`	Initial capitalize `s`
`s.count(ss {,start {,end}})`	Count the occurrences of `ss` in `s[start:end]`
`s.startswith(str {, start {, end}}) s.endswith(str {, start {, end}})`	Test to see if `s` starts with `str` Test to see if `s` ends with `str`
`s.expandtabs({size})`	Replace tabs with spaces, default `size` is 8
`s.find(str {, start {, end}}) s.rfind(str {, start {, end}})`	Finds first index of `str` in `s`; if not found, the result is -1. `rfind` searches right to left.
`s.index(str {, start {, end}}) s.rindex(str {, start {, end}})`	Finds first index of `str` in `s`; if not found: raise `ValueError`. `rindex` searches right to left.
`s.isalnum`	Test to see if the string is alphanumeric
`s.isalpha`	Test to see if the string is alphabetic
`s.isnum`	Test to see if the string is numeric
`s.isupper`	Test to see if the string is all uppercase
`s.islower`	Test to see if the string is all lowercase
`s.isspace`	Test to see if the string is all whitespace
`s.istitle`	Test to see if the string is a sequence of initial cap alphanumeric strings
`s.lower() s.upper() s.swapcase() s.title()`	Convert to all lower case Convert to all upper case Convert to all opposite case Convert to all title case
`s.join(seq)`	Join the strings in `seq` with `s` as the separator
`s.splitlines({keep})`	Split `s` into lines, if keep is `true`, keep the new lines
`s.split({sep {, max}})`	Split `s` into "words" using `sep` (default `sep` is a white space) for up to `max` times
`s.ljust(width) s.rjust(width) s.center(width) s.zfill(width)`	Left justify the string in a field `width` wide Right justify the string in a field `width` wide center justify the string in a field `width` wide Fill with 0.
`s.lstrip() s.rstrip() s.strip()`	Remove leading white space Remove trailing white space Remove leading and trailing white space
`s.translate(str {,delc})`	Translate `s` using table, after removing any characters in `delc`. `str` should be a string with length `== 256`.
`s.replace(old, new {, max})`	Replaces all or `max` occurrences of string `old` with string `new`