Underscore.js _.iterators.select() Method
Last Updated :
08 Jul, 2021
With the help of _.iterators.select() method, we can get the values from iteration function whenever we got true from unary predicate function when we invoked the iterator by using this method.
Syntax:
_.iterators.select(iter, unaryPredicateFn)
Parameter: This method accepts two parameter as mentioned above and described below:
- iter: This parameter holds the iterator list of the array.
- unaryPredicateFn: This parameter holds the unaryPredicateFn function key.
Return value: Return the values from iteration function.
Note: To execute the below examples you have to install the underscore-contrib library by using this command prompt we have to execute the following command.
npm install underscore-contrib
Example 1: In this example, we can see that by using _.iterators.select() method, we are able to get the values from iteration function whenever we got true from unary predicate function every time it invoked.
Javascript
var _ = require( 'underscore-contrib' );
var iter = _.iterators.List([ "ABC" , "Geeks" , "XYZ" ,
"for" , "Geeks" ]);
function isGFG (val) {
if (val == "Geeks" ) {
return true ;
} else if (val == "for" ) {
return true ;
} else {
return false ;
}
}
var geek = _.iterators.select(iter, isGFG);
for ( var i = 0; i < 5; i++) {
console.log(geek());
}
|
Output :
Geeks
for
Geeks
Example 2:
Javascript
var _ = require( 'underscore-contrib' );
var iter = _.iterators.List([1, 2, 3, 4, 5, 6, 7]);
function isOdd (val) {
if (val%2 == 0) {
return false ;
} else {
return true ;
}
}
var geek = _.iterators.select(iter, isOdd);
for ( var i = 0; i < 7; i++) {
console.log(geek());
}
|
Output :
1
3
5
7
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