Test if number is odd or even

Question

What is the simplest most basic way to find out if a number variable is odd or even in PHP  Is it something to do with mod   I ve tried a few scripts but   google isn t delivering at the moment

User · Answer

Another option is a simple bit checking   n  amp  1   for example   if    num  amp  1         odd   else       even

User · Answer

All even numbers divided by 2 will result in an integer   number   4  if is int  number 2        echo  Integer      else      echo  Not Integer

User · Answer

Another option is to check if the last digit is an even number     value    1024     A Number  even   array 0  2  4  6  8   if in array substr  value  -1   even         Even Number  else       Odd Number     Or to make it faster  use isset   instead of array search     value    1024     A Number  even   array 0   gt  1  2   gt  1  4   gt  1  6   gt  1  8   gt  1   if isset  even substr  value  -1          Even Number  else       Odd Number     Or to make it more faster  beats mod operator at times      even   array 0  2  4  6  8   if in array substr  number  -1   even         Even Number  else       Odd Number     Here is the time test as a proof to my findings

User · Answer

PHP is converting null and an empty string automatically to a zero  That happens with modulo as well  Therefor will the code  number   2    0 or    number  amp  1   with value  number      or  number   null result in true  I test it therefor somewhat more extended  function testEven  pArg       if is int  pArg      true            p     pArg   2           if  p     0               print  quot The input   quot   pArg  quot   is even  lt br gt  quot            else              print  quot The input   quot   pArg  quot   is odd  lt br gt  quot                  else          print  quot The input   quot   pArg  quot   is not a number  lt br gt  quot            The print is there for testing purposes  hence in practice it becomes  function testEven  pArg       if is int  pArg     true           return  pArg 2            return false     This function returns 1 for any odd number  0 for any even number and false when it is not a number  I always write     true or     false to let myself  and other programmers  know that the test is as intended

User · Answer

checking even and odd  num  14    even     num   2    0    odd     num   2    0    if  even       echo  Number is even      else       echo  Number is odd

User · Answer

Check Even Or Odd Number Without Use Condition And Loop Statement    This work for me      x000D   x000D    document  ready function    x000D          btn even odd   click function    x000D          var arr     Even   Odd    x000D          var num even odd       num even odd   val    x000D              ans even odd   html arr num even odd   2    x000D          x000D      x000D   lt  DOCTYPE html gt  x000D   lt html gt  x000D   lt head gt  x000D   lt script src  https   cdnjs cloudflare com ajax libs jquery 3 3 1 jquery min js  gt  lt  script gt  x000D       lt title gt Check Even Or Odd Number Without Use Condition And Loop Statement  lt  title gt  x000D   lt  head gt  x000D   lt body gt  x000D   lt h4 gt Check Even Or Odd Number Without Use Condition And Loop Statement  lt  h4 gt  x000D   lt table gt  x000D       lt tr gt  x000D           lt th gt Enter A Number   lt  th gt  x000D           lt td gt  lt input type  text  name  num even odd  id  num even odd  placeholder  Enter Only Number  gt  lt  td gt  x000D       lt  tr gt  x000D       lt tr gt  x000D           lt th gt Your Answer Is   lt  th gt  x000D           lt td id  ans even odd  style  font-size 15px color gray font-weight 900   gt  lt  td gt  x000D       lt  tr gt  x000D       lt tr gt  x000D           lt td gt  lt input type  button  name  btn even odd  id  btn even odd  value  submit  gt  lt  td gt  x000D       lt  tr gt  x000D   lt  table gt  x000D   lt  body gt  x000D   lt  html gt  x000D   x000D   x000D

User · Answer

This code checks if the number is odd or even in PHP  In the example  a is 2 and you get even number  If you need odd then change the  a value   a 2  if  a  2    0       echo   lt h3 gt This Number is  lt b gt  a lt  b gt  Even lt  h3 gt     else      echo   lt h3 gt This Number is  lt b gt  a lt  b gt  Odd lt  h3 gt

User · Answer

I am making an assumption that there is a counter already in place  in  i which is incremented at the end of a loop  This works for me using a shorthand query    row pos     i  amp  1     odd     even     So what does this do  well it queries the statement we are making in essence  i is odd  depending whether its true or false will decide what gets returned  The returned value populates our variable  row pos  My use of this is to place it inside the foreach loop  right before i need it  This makes it a very efficient one liner to give me the appropriate class names  this is because i already have a counter for the id s to make use of later in the program  This is a brief example of how i will use this part    lt div class  row-  row pos   gt  random data  lt div gt    This gives me odd and even classes on each row so i can use the correct class and stripe my printed results down the page   The full example of what i use note the id has the counter applied to it and the class has my odd even result applied to it     i 0  foreach   a as  k   gt   v          row pos     i  amp  1     odd     even       echo   lt div id  A  i   class  row-  row pos   gt   v  f name      v  l name    -   v  amount    -   v  date    lt  div gt  n     i        in summary  this gives me a very simple way to create a pretty table

User · Answer

While all of the answers are good and correct  simple solution in one line is    check   9    either   echo   check  amp  1    Odd     Even      or   echo   check   2    Odd     Even      works very well

User · Answer

You were right in thinking mod was a good place to start   Here is an expression which will return true if  number is even  false if odd    number   2    0   Works for every integerPHP value  see as well Arithmetic OperatorsPHP   Example    number   20  if   number   2    0      print  It s even       Output      It s even

User · Answer

Try this    number   10   switch   number 2      case 0   echo  It s even    break   default   echo  It s odd

User · Answer

Try this one with  Input field      lt  php       checking even and odd     echo   lt form action    method  post  gt        echo   lt input type  text  name  num  gt  n       echo   lt button type  submit  name  submit  gt Check lt  button gt  n       echo   lt  form gt          num   0      if    SERVER  REQUEST METHOD       POST           if  empty   POST  num                numErr     lt span style   color  red   gt Number is required  lt  span gt            echo  numErr          die            else              num     POST  num                   even     num   2    0        odd     num   2    0       if   num  gt  0           if  even               echo  Number is even              else               echo  Number is odd                    else           echo  Not a number                  gt

User · Answer

before   microtime true     n   1000     numbers   range 1  n     cube numbers   array map  cube   numbers    function cube  n              msg   even              if  n 2   0            msg    odd                            return  The Number is  n is    msg     foreach  cube numbers as  cube       echo  cube     lt br  gt        after   microtime true    echo  after- before   seconds

User · Answer

bool   number  amp  1    or    bool     number  amp  1

User · Answer

Yes using the mod   even     num   2    0    odd     num   2    0

User · Answer

I did a bit of testing  and found that between mod  is int and the  amp -operator  mod is the fastest  followed closely by the  amp -operator  is int is nearly 4 times slower than mod   I used the following code for testing purposes         number   13    before   microtime true   for   i 0   i lt 100000   i           test     number 2 true false      after   microtime true    echo  after- before   seconds mod lt br gt      before   microtime true   for   i 0   i lt 100000   i           test     is int  number 2  true false      after   microtime true    echo  after- before   seconds is int lt br gt      before   microtime true   for   i 0   i lt 100000   i           test     number amp 1 true false      after   microtime true    echo  after- before   seconds  amp  operator lt br gt      The results I got were pretty consistent  Here s a sample   0 041879177093506 seconds mod 0 15969395637512 seconds is int 0 044223070144653 seconds  amp  operator

[php] Test if number is odd or even

Examples related to php

Examples related to variables

Examples related to numbers