# Strings¶

You have worked with them for a while now: strings. In principle strings are containers of characters in a certain order. As such they are somewhat similar to lists <list>, and also support, e.g., indexing.

>>> my_first_string = 'Hello, World!'
>>> my_first_string[7:]
'World!'
>>> my_first_string[::-1]
'!dlroW ,olleH'


They offer a large amount of ways to work with text, of which a few selected ones are outlined in the following.

## lower¶

Returns the lowercase version of the string.

>>> 'Hello, World!'.lower()
'hello, world!'


## upper¶

Returns the uppercase version of the string.

>>> 'Hello, World!'.upper()
'HELLO, WORLD!'


## split¶

Working with a whole string at once is needlessly complicated in many cases. Hence the Python standard library offers a way to take a string apart: str.split()

>>> some_string = 'My first string'
>>> some_string.split()
['My', 'first', 'string']


By default it splits to an arbitrary amount of whitespace

>>> some_string = 'My     second     string'
>>> some_string.split()
['My', 'second', 'string']


Note

In Python whitespace is everything you can not directly see like spaces, tabs (\t in strings), and newlines (\n in strings).

but you can also specify another string which is used to split the other string apart:

>>> some_string = '0.1, 0.2, 0.3, 0.4, 0.5'
>>> some_string.split(',')
['0.1', ' 0.2', ' 0.3', ' 0.4', ' 0.5']


The string that is used to split with is consumed in the process. So to get rid of the additional whitespace you might get the idea to add it to the string used for the splitting

>>> some_string = '0.1, 0.2, 0.3, 0.4, 0.5'
>>> some_string.split(', ')
['0.1', '0.2', '0.3', '0.4', '0.5']


Eventually this might lead to problems if the string format is not strictly kept:

>>> some_string = '0.1,   0.2,0.3, 0.4,  0.5'
>>> some_string.split(', ')
['0.1', '  0.2,0.3', '0.4', ' 0.5']


But Python’s got you covered…

## strip¶

To get rid of unwanted whitespace around a string you can use the str.strip() method:

>>> some_string = '\n\n    So much surrounding whitespace\n\n'
>>> print(some_string)

So much surrounding whitespace

>>> some_string.strip()
'So much surrounding whitespace'


You can also get rid of something else than whitespace by specifying the characters as an argument:

>>> more_string = '...Python...'
>>> more_string.strip('.')
'Python'


Note

The characters you specify as an argument are not seen as a string but as a collection of characters you want to strip of the string:

>>> incantation = 'abracadabra'
>>> incantation.strip('bra')
`