How to take the nth digit of a number in python

Question

I want to take the nth digit from an N digit number in python   For example   number   9876543210 i   4 number i    should return 6   How can I do something like that in python  Should I change it to string first and then change it to int for the calculation

User · Answer

Ok  first of all  use the str   function in python to turn  number  into a string  number   9876543210  declaring and assigning number   str number   converting   Then get the index  0   1  4   3 in index notation  use int   to turn it back into a number  print int number 3     printing the int format of the string  number  s index of 3 or  6    if you like it in the short form  print int str 9876543210  3     condensed code lol  also no more variable  number

User · Answer

Here s my take on this problem  I have defined a function  index  which takes the number and the input index and outputs the digit at the desired index  The enumerate method operates on the strings  therefore the number is first converted to a string  Since the indexing in Python starts from zero  but the desired functionality requires it to start with 1  therefore a 1 is placed in the enumerate function to indicate the start of the counter  def index number  i        for p num in enumerate str number  1            if p    i              print num

User · Answer

I would recommend adding a boolean check for the magnitude of the number  I m converting a high milliseconds value to datetime  I have numbers from 2 to 200 000 200 so 0 is a valid output  The function as  Chris Mueller has it will return 0 even if number is smaller than 10  n   def get digit number  n       return number    10  n   10  get digit 4231  5    0     def get digit number  n       if number - 10  n  lt  0          return False     return number    10  n   10  get digit 4321  5    False     You do have to be careful when checking the boolean state of this return value  To allow 0 as a valid return value  you cannot just use if get digit   You have to use if get digit is False  to keep 0 from behaving as a false value

User · Answer

First treat the number like a string  number   9876543210 number   str number    Then to get the first digit   number 0    The fourth digit   number 3    EDIT   This will return the digit as a character  not as a number   To convert it back use   int number 0

User · Answer

You can do it with integer division and remainder methods  def get digit number  n       return number    10  n   10  get digit 987654321  0    1  get digit 987654321  5    6   The    performs integer division by a power of ten to move the digit to the ones position  then the   gets the remainder after division by 10   Note that the numbering in this scheme uses zero-indexing and starts from the right side of the number

User · Answer

I m very sorry for necro-threading but I wanted to provide a solution without converting the integer to a string  Also I wanted to work with more computer-like thinking so that s why the answer from Chris Mueller wasn t good enough for me  So without further ado  import math  def count number number       counter   0     counter number   number     while counter number  gt  0          counter number     10         counter    1     return counter   def digit selector number  selected digit  total       total counter   total     calculated select   total counter - selected digit     number selected   int number   math pow 10  calculated select       while number selected  gt  10          number selected -  10     return number selected   def main        x   1548731588     total digits   count number x      digit 2   digit selector x  2  total digits      return print digit 2    if   name         main         main    which will print  5  Hopefully someone else might need this specific kind of code  Would love to have feedback on this aswell  This should find any digit in a integer  Flaws  Works pretty ok but if you use this for long numbers then it ll take more and more time  I think that it would be possible to see if there are multiple thousands etc and then substract those from number selected but that s maybe for another time    Usage  You need every line from 1-21  Then you can call first count number to make it count your integer  x   1548731588 total digits   count number x   Then read use the digit selector function as follows   digit selector  insert your integer here    which digit do you want to have   starting from the most left digit as 1     How many digits are there in total     If we have 1234567890  and we need 4 selected  that is the 4th digit counting from left so we type  4   We know how many digits there are due to using total digits  So that s pretty easy  Hope that explains everything  Han PS  Special thanks for CodeVsColor for providing the count number function  I used this link  https   www codevscolor com count-number-digits-number-python to help me make the digit selector work

User · Answer

I was curious about the relative speed of the two popular approaches - casting to string and using modular arithmetic - so I profiled them and was surprised to see how close they were in terms of performance   My use-case was slightly different  I wanted to get all digits in the number   The string approach gave           10000002 function calls in 1 113 seconds     Ordered by  cumulative time     ncalls  tottime  percall  cumtime  percall filename lineno function   10000000    1 113    0 000    1 113    0 000 sandbox py 1 get digits str          1    0 000    0 000    0 000    0 000 cProfile py 133   exit            1    0 000    0 000    0 000    0 000  method  disable  of   lsprof Profiler  objects   While the modular arithmetic approach gave            10000002 function calls in 1 102 seconds     Ordered by  cumulative time     ncalls  tottime  percall  cumtime  percall filename lineno function   10000000    1 102    0 000    1 102    0 000 sandbox py 6 get digits mod          1    0 000    0 000    0 000    0 000 cProfile py 133   exit            1    0 000    0 000    0 000    0 000  method  disable  of   lsprof Profiler  objects   There were 10 7 tests run with a max number size less than 10 28  Code used for reference  def get digits str num       for n str in str num           yield int n str    def get digits mod num  radix 10        remaining   num     yield remaining   radix      while remaining    remaining    radix          yield remaining   radix   if   name         main          import cProfile     import random      random inputs    random randrange 0  10000000000000000000000000000  for   in range 10000000        with cProfile Profile   as str profiler          for rand num in random inputs              get digits str rand num       str profiler print stats sort  cumtime        with cProfile Profile   as mod profiler          for rand num in random inputs              get digits mod rand num       mod profiler print stats sort  cumtime

[python] How to take the nth digit of a number in python

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