\(\newcommand{L}[1]{\| #1 \|}\newcommand{VL}[1]{\L{ \vec{#1} }}\newcommand{R}[1]{\operatorname{Re}\,(#1)}\newcommand{I}[1]{\operatorname{Im}\, (#1)}\)
String literals in Python¶
A string literal is where you specify the contents of a string in a program.
>>> a = 'A string'
Here ‘A string’ is a string literal. The variable a is a string variable, or, better put in Python, a variable that points to a string.
String literals can use single or double quote delimiters.
>>> a = 'A string' # string literal with single quotes
>>> b = "A string" # string literal with double quotes
>>> b == a # there is no difference between these strings
True
Literal strings with single quote delimiters can use double quotes inside them without any extra work.
>>> print('Single quoted string with " is no problem')
Single quoted string with " is no problem
If you need an actual single quote character inside a literal string delimited by single quotes, you can use the backslash character before the single quote, to tell Python not to terminate the string:
>>> print('Single quoted string containing \' is OK with backslash')
Single quoted string containing ' is OK with backslash
Likewise for double quotes:
>>> print("Double quoted string with ' is no problem")
Double quoted string with ' is no problem
>>> print("Double quoted string containing \" is OK with backslash")
Double quoted string containing " is OK with backslash
Some characters preceded by a backslash have special meaning. For example:
>>> print('Backslash before "n", as in \n, inserts a new line character') #doctest: +NORMALIZE_WHITESPACE
Backslash before "n", as in
, inserts a new line character
If you do not want the backslash to have this special meaning, prefix your string literal with ‘r’, meaning “raw”:
>>> print(r'Prefixed by "r" the \n no longer inserts a new line')
Prefixed by "r" the \n no longer inserts a new line
You can use triple quotes to enclose strings with more than one line:
>>> print('''This string literal
... has more than one
... line''')
This string literal
has more than one
line
Triple quotes can use single or double quote marks:
>>> print("""This string literal
... also has more than one
... line""")
This string literal
also has more than one
line