Convert a Python list with strings all to lowercase or uppercase

Question

I have a python list variable that contains strings  Is there a python function that can convert all the strings in one pass to lowercase and vice versa  uppercase

User · Answer

mylist     Mixed Case One    Mixed Case Two    Mixed Three   print list map lambda x  x lower    mylist    print list map lambda x  x upper    mylist

User · Answer

It can be done with list comprehensions  These basically take the form of  function-of-item for item in some-list   For example  to create a new list where all the items are lower-cased  or upper-cased in the second snippet   you would use    gt  gt  gt   x lower   for x in   A   B   C      a    b    c     gt  gt  gt   x upper   for x in   a   b   c      A    B    C     You can also use the map function    gt  gt  gt  map lambda x x lower     A   B   C      a    b    c    gt  gt  gt  map lambda x x upper     a   b   c      A    B    C

User · Answer

Python3 6 8  In  1   a    which option is the fastest                                                                                                                                              In  2     timeit             join a  upper    762 ns    11 4 ns per loop  mean    std  dev  of 7 runs  1000000 loops each   In  3     timeit           map lambda x x upper    a   209 ns    5 73 ns per loop  mean    std  dev  of 7 runs  1000000 loops each   In  4     timeit           map str upper   i for i in a    1 18   s    11 3 ns per loop  mean    std  dev  of 7 runs  1000000 loops each   In  5     timeit           i upper   for i in a   3 2   s    64 1 ns per loop  mean    std  dev  of 7 runs  100000 loops each    If you need a string or list as the output and not an iterator  this is for Python3   compare    join string  upper   option to this   In  10     timeit             i for i in map lambda x x upper    a    4 32   s    112 ns per loop  mean    std  dev  of 7 runs  100000 loops each

User · Answer

Besides being easier to read  for many people   list comprehensions win the speed race  too     python2 6 -m timeit   x lower   for x in   A   B   C     1000000 loops  best of 3  1 03 usec per loop   python2 6 -m timeit   x upper   for x in   a   b   c     1000000 loops  best of 3  1 04 usec per loop    python2 6 -m timeit  map str lower   A   B   C     1000000 loops  best of 3  1 44 usec per loop   python2 6 -m timeit  map str upper   a   b   c     1000000 loops  best of 3  1 44 usec per loop    python2 6 -m timeit  map lambda x x lower     A   B   C     1000000 loops  best of 3  1 87 usec per loop   python2 6 -m timeit  map lambda x x upper     a   b   c     1000000 loops  best of 3  1 87 usec per loop

User · Answer

gt  gt  gt  map str lower   A   B   C      a    b    c

User · Answer

A much simpler version of the top answer is given here by  Amorpheuses    With a list of values in val   valsLower    item lower   for item in vals    This worked well for me with an f   open   text source

User · Answer

For this sample the comprehension is fastest     python -m timeit -s  s   one   two   three   1000    x upper for x in s   1000 loops  best of 3  809 usec per loop    python -m timeit -s  s   one   two   three   1000   map str upper s   1000 loops  best of 3  1 12 msec per loop    python -m timeit -s  s   one   two   three   1000   map lambda x x upper   s   1000 loops  best of 3  1 77 msec per loop

User · Answer

a student asking  another student with the same problem answering      fruits   orange    grape    kiwi    apple    mango    fig    lemon   newList      for fruit in fruits      newList append fruit upper    print newList

User · Answer

You could try using   my list     india    america    china    korea    def capitalize list item       return item upper    print list map capitalize list  my list

User · Answer

List comprehension is how I d do it  it s the  Pythonic  way  The following transcript shows how to convert a list to all upper case then back to lower   pax paxbox7    python3 Python 3 5 2  default  Nov 17 2016  17 05 23    GCC 5 4 0 20160609  on linux Type  help    copyright    credits  or  license  for more information    gt  gt  gt  x     one    two    three     x   one    two    three     gt  gt  gt  x    element upper   for element in x    x   ONE    TWO    THREE     gt  gt  gt  x    element lower   for element in x    x   one    two    three

User · Answer

If your purpose is to matching with another string by converting in one pass  you can use str casefold   as well    This is useful when you have non-ascii characters and matching with ascii versions eg  ma  e vs masse  Though str lower or str upper fails in such cases  str casefold   will pass   This is available in Python 3 and the idea is discussed in detail with the answer https   stackoverflow com a 31599276 4848659    gt  gt  gt str  Hello World    gt  gt  gt print str lower     hello world  gt  gt  gt print str upper     HELLO WOLRD  gt  gt  gt print str casefold     hello world

User · Answer

Solution    gt  gt  gt  s       gt  gt  gt  p     This    That    There    is    apple    gt  gt  gt   s append i lower    if not i islower   else s append i  for i in p   gt  gt  gt  s  gt  gt  gt    this    that    there    is   apple     This solution will create a separate list containing the lowercase items  regardless of their original case  If the original case is upper then the list s will contain lowercase of the respective item in list p  If the original case of the list item is already lowercase in list p then the list s will retain the item s case and keep it in lowercase  Now you can use list s instead of list p

User · Answer

If you are trying to convert all string to lowercase in the list  You can use pandas    import pandas as pd  data     Study    Insights    pd d   list pd Series data  str lower      output     study    insights

[python] Convert a Python list with strings all to lowercase or uppercase

Examples related to python

Examples related to list