10.9: Lists and strings
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A string is a sequence of characters and a list is a sequence of values, but a list of characters is not the same as a string. To convert from a string to a list of characters, you can use
>>> s = 'spam' >>> t = list(s) >>> t ['s', 'p', 'a', 'm']
list is the name of a built-in function, you should avoid using it as a variable name. I also avoid l because it looks too much like 1. So that’s why I use
list function breaks a string into individual letters. If you want to break a string into words, you can use the
>>> s = 'pining for the fjords' >>> t = s.split() >>> t ['pining', 'for', 'the', 'fjords']
An optional argument called a delimiter specifies which characters to use as word boundaries. The following example uses a hyphen as a delimiter:
>>> s = 'spam-spam-spam' >>> delimiter = '-' >>> t = s.split(delimiter) >>> t ['spam', 'spam', 'spam']
join is the inverse of
split. It takes a list of strings and concatenates the elements.
join is a string method, so you have to invoke it on the delimiter and pass the list as a parameter:
>>> t = ['pining', 'for', 'the', 'fjords'] >>> delimiter = ' ' >>> s = delimiter.join(t) >>> s 'pining for the fjords'
In this case the delimiter is a space character, so
join puts a space between words. To concatenate strings without spaces, you can use the empty string,
'', as a delimiter.