Break string into list of characters in Python

Question

Essentially I want to suck a line of text from a file  assign the characters to a list  and create a list of all the separate characters in a list -- a list of lists   At the moment  I ve tried this   fO   open filename   rU   fL   fO readlines     That s all I ve got  I don t quite know how to extract the single characters and assign them to a new list   The line I get from the file will be something like   fL    FHFF HHXH XXXX HFHX    I want to turn it into this list  with each single character on its own     F    H    F    F    H

User · Accepted Answer

Strings are iterable  just like a list    I m interpreting that you really want something like   fd   open filename  rU   chars      for line in fd     for c in line         chars append c    or  fd   open filename   rU   chars      for line in fd      chars extend line    or  chars      with open filename   rU   as fd      map chars extend  fd    chars would contain all of the characters in the file

User · Answer

I m a bit late it seems to be  but     a  hello  print list a      h   e   l   l    o

User · Answer

python    3 5  Version 3 5 onwards allows the use of PEP 448 - Extended Unpacking Generalizations    gt  gt  gt  string    hello   gt  gt  gt    string    h    e    l    l    o     This is a specification of the language syntax  so it is faster than calling list    gt  gt  gt  from timeit import timeit  gt  gt  gt  timeit  list  hello     0 3042821969866054  gt  gt  gt  timeit     hello     0 1582647830073256

User · Answer

fO   open filename   rU   lst   list fO read

User · Answer

a  hello world  map lambda x x  a         h    e    l    l    o         w    o    r    l    d     An easy way is using function    map

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

So to add the string hello to a list as individual characters  try this   newlist      newlist  0     hello  print  newlist       h   e   l   l   o     However  it is easier to do this   splitlist   list newlist  print  splitlist

User · Answer

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

[python] Break string into list of characters in Python

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