How to check if an integer is within a range

Question

Is there a way to test a range without doing this redundant code   if   int gt  min  amp  amp   int lt  max       Like a function   function testRange  int  min  max       return   min lt  int  amp  amp   int lt  max       usage   if  testRange  int  min  max         Does PHP have such built-in function  Or any other way to do it

User · Answer

There s filter var   as well and it s the native function which checks range  It doesn t give exactly what you want  never returns true   but with  cheat  we can change it    I don t think it s a good code as for readability  but I show it s as a possibility   return  filter var  someNumber  FILTER VALIDATE INT    options    gt    min range    gt   min   max range    gt   max        false    Just fill  someNumber   min and  max  filter var with that filter returns either boolean false when number is outside range or the number itself when it s within range  The expression      false  makes function return true  when number is within range   If you want to shorten it somehow  remember about type casting  If you would use    it would be false for number 0 within range -5   5  while it should be true   The same would happen if you would use type casting   bool        EXAMPLE OF WRONG USE  GIVES WRONG RESULTS WITH  0   bool filter var  someNumber  FILTER VALIDATE INT    options    gt    min range    gt   min   max range    gt   max    if  filter var  someNumber  FILTER VALIDATE INT    options    gt    min range    gt   min   max range    gt   max           Imagine that  from other answer    if in array  userScore  range -5  5    echo  your score is correct   else echo  incorrect  enter again     If user would write empty value   userScore       it would be correct  as in array is set here for default  non-strict more and that means that range creates 0 as well  and       0  non-strict   but        0  if you would use strict mode   It s easy to miss such things and that s why I wrote a bit about that  I was learned that strict operators are default  and programmer could use non-strict only in special cases  I think it s a good lesson  Most examples here would fail in some cases because non-strict checking   Still I like filter var and you can use above  or below if I d got so  upped      functions and make your own callback which you would use as FILTER CALLBACK filter  You could return bool or even add openRange parameter  And other good point  you can use other functions  e g  checking range of every number of array or POST GET values  That s really powerful tool

User · Answer

There is no builtin function  but you can easily achieve it by calling the functions min   and max   appropriately      Limit integer between 1 and 100000  var   max min  var  100000   1

User · Answer

I don t think you ll get a better way than your function   It is clean  easy to follow and understand  and returns the result of the condition  no return         true   false mess

User · Answer

Tested your 3 ways with a 1000000-times-loop   t1 test1    val  gt    min  amp  amp   val  lt    max   0 3823 ms  t2 test2   in array  val  range  min   max    9 3301 ms  t3 test3   max min  var   max    min      val     0 7272 ms  T1 was fastest  it was basicly this   function t1  val   min   max      return   val  gt    min  amp  amp   val  lt    max

User · Answer

You could do it using in array   combined with range    if  in array  value  range  min   max             Value is in range     Note As has been pointed out in the comments however  this is not exactly a great solution if you are focussed on performance  Generating an array  escpecially with larger ranges  will slow down the execution

User · Answer

I m not able to comment  not enough reputation  so I ll amend Luis Rosety s answer here   function between  n   a   b        return   n- a    n- b   lt   0      This function works also in cases where n    a or n    b   Proof  Let n belong to range  a b   where  a b  is a subset of real numbers   Now a  lt   n  lt   b  Then n-a    0 and n-b  lt   0  That means that  n-a   n-b   lt   0   Case b  lt   n  lt   a works similarly

User · Answer

Most of the given examples assume that for the test range   a   b     a  lt    b  i e  the range extremes are in lower - higher order and most assume that all are integer numbers  But I needed a function to test if  n was between  a and  b  as described here     Check if  n is between  a and  b even if       a  lt   b        a  gt   b      a    b  All numbers can be real  not only integer    There is an easy way to test  I base the test it in the fact that   n- a  and   n- b  have different signs when  n is between  a and  b  and the same sign when  n is outside the  a   b range  This function is valid for testing increasing  decreasing  positive and negative numbers  not limited to test only integer numbers   function between  n   a   b        return    a   n  amp  amp   b   n    true     n- a    n- b  lt 0

User · Answer

Using comparison operators is way  way faster than calling any function  I m not 100  sure if this exists  but I think it doesn t

[php] How to check if an integer is within a range?

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