Convert all strings in a list to int

Question

In Python  I want to convert all strings in a list to integers   So if I have   results     1    2    3     How do I make it   results    1  2  3

User · Accepted Answer

Use the map function  in Python 2 x    results   map int  results    In Python 3  you will need to convert the result from map to a list   results   list map int  results

User · Answer

If your list contains pure integer strings  the accepted awnswer is the way to go  This solution will crash if you give it things that are not integers  So  if you have data that may contain ints  possibly floats or other things as well - you can leverage your own function with errorhandling  def maybeMakeNumber s        quot  quot  quot Returns a string  s  into a integer if possible  a float if needed or     returns it as is  quot  quot  quot         handle None   quot  quot   0     if not s          return s     try          f   float s          i   int f          return i if f    i else f     except ValueError          return s  data     quot unkind quot    quot data quot    quot 42 quot   98   quot 47 11 quot    quot of mixed quot    quot types quot    converted   list map maybeMakeNumber  data   print converted   Output    unkind    data   42  98  47 11   of mixed    types     To also handle iterables inside iterables you can use this helper  from collections abc import Iterable  Mapping  def convertEr iterab        quot  quot  quot Tries to convert an iterable to list of floats  ints or the original thing     from the iterable  Converts any iterable  tuple set       to itself in output      Does not work for Mappings  - you would need to check abc Mapping and handle      things like  1 42   quot 1 quot  84  when converting them - so they come out as is  quot  quot  quot       if isinstance iterab  str           return maybeMakeNumber iterab       if isinstance iterab  Mapping           return iterab      if isinstance iterab  Iterable           return  iterab   class   convertEr p  for p in iterab    data     quot unkind quot    1  3  quot 1 quot  42    quot data quot    quot 42 quot   98   quot 47 11 quot    quot of mixed quot              quot 0 quot    quot 8 quot     quot 15 quot    quot things quot     quot 3 141 quot     quot types quot    converted   convertEr data  print converted   Output    unkind    1  3   1   42    data   42  98  47 11   of mixed      0  8    things   15   3 141    types     sets are unordered  hence diffrent order

User · Answer

Use a list comprehension   results    int i  for i in results    e g    gt  gt  gt  results     1    2    3    gt  gt  gt  results    int i  for i in results   gt  gt  gt  results  1  2  3

User · Answer

You can do it simply in one line when taking input   int i  for i in input   split  quot  quot     Split it where you want  If you want to convert a list not list simply put your list name in the place of input   split  quot  quot

User · Answer

Here is a simple solution with explanation for your query   a   1   2   3   4   5    The integer represented as a string in this list  b     Fresh list  for i in a   Declaring variable  i  as an item in the list  a        b append int i    Look below for explanation  print b   Here  append   is used to add items   i e integer version of string  i  in this program   to the end of the list  b   Note  int   is a function that helps to convert an integer in the form of string  back to its integer form  Output console   1  2  3  4  5   So  we can convert the string items in the list to an integer only if the given string is entirely composed of numbers or else an error will be generated

User · Answer

I also want to add Python   Converting all strings in list to integers Method  1   Naive Method   Python3 code to demonstrate    converting list of strings to int    using naive method     initializing list  test list     1    4    3    6    7       Printing original list  print   quot Original list is    quot    str test list       using naive method to    perform conversion  for i in range 0  len test list         test list i    int test list i            Printing modified list  print   quot Modified list is    quot    str test list     Output  Original list is     1    4    3    6    7   Modified list is    1  4  3  6  7   Method  2   Using list comprehension   Python3 code to demonstrate    converting list of strings to int    using list comprehension     initializing list  test list     1    4    3    6    7       Printing original list  print   quot Original list is    quot    str test list       using list comprehension to    perform conversion  test list    int i  for i in test list           Printing modified list  print   quot Modified list is    quot    str test list     Output  Original list is     1    4    3    6    7   Modified list is    1  4  3  6  7   Method  3   Using map     Python3 code to demonstrate    converting list of strings to int    using map       initializing list  test list     1    4    3    6    7       Printing original list  print   quot Original list is    quot    str test list       using map   to    perform conversion  test list   list map int  test list            Printing modified list  print   quot Modified list is    quot    str test list     Output  Original list is     1    4    3    6    7   Modified list is    1  4  3  6  7

User · Answer

A little bit more expanded than list comprehension but likewise useful   def str list to int list str list       n   0     while n  lt  len str list           str list n    int str list n           n    1     return str list    e g    gt  gt  gt  results     1    2    3    gt  gt  gt  str list to int list results   1  2  3    Also    def str list to int list str list       int list    int n  for n in str list      return int list

[python] Convert all strings in a list to int

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