Switch Case To/Between | 易学教程

问题

Is there a way in Javascript to compare one integer with another through switch case structures without using if statements?

E.g.

switch(integer) {
    case 1 to 10:
        break;
    case 11 to 20:
        break;
    case 21 to 30:
        break;
}

回答1:

You can do some math manipulations.

switch(Math.ceil(integer/10)) {
    case 1: // Integer is between 1-10
        break;
    case 2: // Integer is between 11-20
        break;
    case 3: // Integer is between 21-30
        break;
}

回答2:

There is a way, yes. I'm pretty sure I'd use an if/else structure in my own code, but if you're keen to use a switch the following will work:

switch(true) {
   case integer >= 1 && integer <= 10:
      // 1-10
      break;
   case integer >= 11 && integer <= 20: 
      // 11-20
      break;
   case integer >= 21 && integer <= 30:
      // 21-30
      break;
}

Of course if you wanted to avoid having to code >= && <= on every case you could define your own isInRange(num,min,max) type function to return a boolean and then say:

switch (true) {
   case isInRange(integer,1,10):
      // 1-10
      break;
   // etc
}

回答3:

As stated in my comment, you can't do that. However, you could define an inRange function:

function inRange(x, min, max) {
    return min <= x && x <= max;
}

and use it together with if - else if. That should make it quite easy to read:

if(inRange(integer, 1, 10)) {

}
else if(inRange(integer, 11, 20)) {

}

//...

回答4:

Posting for "cool" syntax :P

if( integer in range(0, 10 ) ) {

}
else if ( integer in range( 11, 20 ) ) {



}
else if ( integer in range( 21, 30 ) ) {



}

function range( min, max ){
var o = {}, i ;
    for( i = min; i <= max; ++i ) {
    o[i] = !0;
    }
return o;
}

来源：https://stackoverflow.com/questions/8528869/switch-case-to-between

标签

javascript

switch-statement