Break string into list of characters in Python [duplicate]

Answer 1

python >= 3.5

Version 3.5 onwards allows the use of PEP 448 - Extended Unpacking Generalizations:

>>> string = 'hello'
>>> [*string]
['h', 'e', 'l', 'l', 'o']

This is a specification of the language syntax, so it is faster than calling list:

>>> from timeit import timeit
>>> timeit("list('hello')")
0.3042821969866054
>>> timeit("[*'hello']")
0.1582647830073256

Answer 2

Or use a fancy list comprehension, which are supposed to be "computationally more efficient", when working with very very large files/lists

fd = open(filename,'r')
chars = [c for line in fd for c in line if c is not " "]
fd.close()

Btw: The answer that was accepted does not account for the whitespaces...

Answer 3

I'm a bit late it seems to be, but...

a='hello'
print list(a)
# ['h','e','l','l', 'o']

Answer 4

Because strings are (immutable) sequences they can be unpacked similar to lists:

with open(filename, 'rU') as fd:
    multiLine = fd.read()
    *lst, = multiLine

When running map(lambda x: x, multiLine) this is clearly more efficient, but in fact it returns a map object instead of a list.

with open(filename, 'rU') as fd:
    multiLine = fd.read()
    list(map(lambda x: x, multiLine))

Turning the map object into a list will take longer than the unpacking method.

Answer 5

You can do this using list:

new_list = list(fL)

Be aware that any spaces in the line will be included in this list, to the best of my knowledge.

Answer 6

In python many things are iterable including files and strings. Iterating over a filehandler gives you a list of all the lines in that file. Iterating over a string gives you a list of all the characters in that string.

charsFromFile = []
filePath = r'path\to\your\file.txt' #the r before the string lets us use backslashes

for line in open(filePath):
    for char in line:
        charsFromFile.append(char) 
        #apply code on each character here

or if you want a one liner

#the [0] at the end is the line you want to grab.
#the [0] can be removed to grab all lines
[list(a) for a in list(open('test.py'))][0]  

.

.

Edit: as agf mentions you can use itertools.chain.from_iterable

His method is better, unless you want the ability to specify which lines to grab list(itertools.chain.from_iterable(open(filename, 'rU)))

This does however require one to be familiar with itertools, and as a result looses some readablity

If you only want to iterate over the chars, and don't care about storing a list, then I would use the nested for loops. This method is also the most readable.