How to split a string into array of characters?

问题:

I\'ve tried to look around the web for answers to splitting a string into an array of characters but I can\'t seem to find a simple method

str.split(//) does not seem to work like Ruby does. Is there a simple way of doing this without looping?

回答1:

>>> s = \"foobar\"
>>> list(s)
[\'f\', \'o\', \'o\', \'b\', \'a\', \'r\']

You need list

回答2:

You take the string and pass it to list()

s = \"mystring\"
l = list(s)
print l

回答3:

You can also do it in this very simple way without list():

>>> [c for c in \"foobar\"]
[\'f\', \'o\', \'o\', \'b\', \'a\', \'r\']

回答4:

I explored another two ways to accomplish this task. It may be helpful for someone.

The first one is easy:

In [25]: a = []
In [26]: s = \'foobar\'
In [27]: a += s
In [28]: a
Out[28]: [\'f\', \'o\', \'o\', \'b\', \'a\', \'r\']

And the second one use map and lambda function. It may be appropriate for more complex tasks:

In [36]: s = \'foobar12\'
In [37]: a = map(lambda c: c, s)
In [38]: a
Out[38]: [\'f\', \'o\', \'o\', \'b\', \'a\', \'r\', \'1\', \'2\']

For example

# isdigit, isspace or another facilities such as regexp may be used
In [40]: a = map(lambda c: c if c.isalpha() else \'\', s)
In [41]: a
Out[41]: [\'f\', \'o\', \'o\', \'b\', \'a\', \'r\', \'\', \'\']

See python docs for more methods

回答5:

The task boils down to iterating over characters of the string and collecting them into a list. The most naïve solution would look like

result = []
for character in string:
    result.append(character)

Of course, it can be shortened to just

result = [character for character in string]

but there still are shorter solutions that do the same thing.

list constructor can be used to convert any iterable (iterators, lists, tuples, string etc.) to list.

>>> list(\'abc\')
[\'a\', \'b\', \'c\']

The big plus is that it works the same in both Python 2 and Python 3.

Also, starting from Python 3.5 (thanks to the awesome PEP 448) it\'s now possible to build a list from any iterable by unpacking it to an empty list literal:

>>> [*\'abc\']
[\'a\', \'b\', \'c\']

This is neater, and in some cases more efficient than calling list constructor directly.

I\'d advise against using map-based approaches, because map does not return a list in Python 3. See How to use filter, map, and reduce in Python 3.

回答6:

If you want to process your String one character at a time. you have various options.

uhello = u\'Hello\\u0020World\'

Using List comprehension:

print([x for x in uhello])

Output:

[\'H\', \'e\', \'l\', \'l\', \'o\', \' \', \'W\', \'o\', \'r\', \'l\', \'d\']

Using map:

print(list(map(lambda c2: c2, uhello)))

Output:

[\'H\', \'e\', \'l\', \'l\', \'o\', \' \', \'W\', \'o\', \'r\', \'l\', \'d\']

Calling Built in list function:

print(list(uhello))

Output:

[\'H\', \'e\', \'l\', \'l\', \'o\', \' \', \'W\', \'o\', \'r\', \'l\', \'d\']

Using for loop:

for c in uhello:
    print(c)

Output:

[\'H\', \'e\', \'l\', \'l\', \'o\', \' \', \'W\', \'o\', \'r\', \'l\', \'d\']

回答7:

simple:

s = \'My\'    
print(list(s))

回答8:

split() inbuilt function will only separate the value on the basis of certain condition but in the single word, it cannot fulfill the condition. So, it can be solved with the help of list(). It internally calls the Array and it will store the value on the basis of an array.

Suppose,

a = \"bottle\"
a.split() // will only return the word but not split the every single char.

a = \"bottle\"
list(a) // will separate [\'b\',\'o\',\'t\',\'t\',\'l\',\'e\']

回答9:

If you wish to read only access to the string you can use array notation directly.

Python 2.7.6 (default, Mar 22 2014, 22:59:38) 
[GCC 4.8.2] on linux2
Type \"help\", \"copyright\", \"credits\" or \"license\" for more information.
>>> t = \'my string\'
>>> t[1]
\'y\'

Could be useful for testing without using regexp. Does the string contain an ending newline?

>>> t[-1] == \'\\n\'
False
>>> t = \'my string\\n\'
>>> t[-1] == \'\\n\'
True

回答10:

Well, much as I like the list(s) version, here\'s another more verbose way I found (but it\'s cool so I thought I\'d add it to the fray):

>>> text = \"My hovercraft is full of eels\"
>>> [text[i] for i in range(len(text))]
[\'M\', \'y\', \' \', \'h\', \'o\', \'v\', \'e\', \'r\', \'c\', \'r\', \'a\', \'f\', \'t\', \' \', \'i\', \'s\', \' \', \'f\', \'u\', \'l\', \'l\', \' \', \'o\', \'f\', \' \', \'e\', \'e\', \'l\', \'s\']

回答11:

from itertools import chain

string = \'your string\'
chain(string)

similar to list(string) but returns a generator that is lazily evaluated at point of use, so memory efficient.

回答12:

I you just need an array of chars:

arr = list(str)

If you want to split the str by a particular str:

# str = \"temp//temps\" will will be [\'temp\', \'temps\']
arr = str.split(\"//\")

回答13:

>>> for i in range(len(a)):
...     print a[i]
... 

where a is the string that you want to separate out. The values \"a[i]\" are the individual character of the the string these could be appended to a list.