Python Language String: Difference between revisions

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Line 17: Line 17:
s1 = 'the color is "red"'
s1 = 'the color is "red"'
s2 = "the shape is 'square'"
s2 = "the shape is 'square'"
</syntaxhighlight>
==Three Single and Three Double Quotes==
Multi-line string literals can be declared using three single quotes or three double quotes. The leading and training space in such strings will also be preserved. The attempt to declare multi-line string literals bounded by single or double quotes results in <code>SyntaxError</code> exceptions.
<syntaxhighlight lang='py'>
s1 = '''
    the color
        is
    "red"
    '''
s2 = """
    the shape
        is
    'square'
    """
print(s1)
print(s2)
</syntaxhighlight>
<syntaxhighlight lang='text'>
    the color
        is
    "red"
    the shape
        is
    'square'
</syntaxhighlight>
</syntaxhighlight>



Revision as of 19:21, 18 June 2022

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'"

Three Single and Three Double Quotes

Multi-line string literals can be declared using three single quotes or three double quotes. The leading and training space in such strings will also be preserved. The attempt to declare multi-line string literals bounded by single or double quotes results in SyntaxError exceptions.

s1 = '''
    the color
        is
    "red"
    '''
s2 = """
    the shape
        is
    'square'
    """
print(s1)
print(s2)
    the color
        is
    "red"


    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

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Python Language String TODELETE