Python Language String
Internal
Overview
String are a Python sequence of characters. Strings are immutable, a string cannot be changed in-place. Python 3 supports the Unicode standard, so Python 3 strings can contain characters from any written language in the world.
Quotes
String literals can be declared using four type of quotes: sigle quotes '...', double quotes "...", triple single quotes '''...''' and triple double quotes """...""".
Single and Double Quotes
s1 = 'abc'
s2 = "xyz"
Declaring string literals bounded by single and double quotes is equivalent. There are two types of quotes to make it possible to create strings that include single and double quotes: a single-quoted string allows specifying double quotes inside and a double-quoted string allows specifying single quotes inside:
s1 = 'the color is "red"'
s2 = "the shape is 'square'"
The [] Operator and String Slices
The [] operator can be used to read strings from the sequence, but not modify the sequence. Because strings are immutable, an attempt to change a character at a specific position in string will throw an TypeError exception:
s = 'abc'
s[0] = 'x'
[...]
TypeError: 'str' object does not support item assignment