I'm trying to figure out why the following piece of code only pops the last 3 items off the array but not the last two.
var test = ['test1','test2','test3','test4','test5'];
console.log('length - '+test.length);
for(var k = 0; k <= test.length; k++) {
var tests = test.pop();
console.log(tests+' - '+k);
}
The results for the above code:
length - 5
(index):30 test5 - 0
(index):30 test4 - 1
(index):30 test3 - 2
Array.prototype.pop method modifies the original array, so of course for-loop will only visit half of the values until array is fully emptied.
What you can do is to use while loop instead:
var test = ['test1', 'test2', 'test3', 'test4', 'test5'];
console.log('length - ' + test.length);
while (test.length) {
var tests = test.pop();
console.log(tests);
}The problem is that the length of the array is changing while the loop is executing, so the test
k <= test.length is changing with each execution.
var test = ['test1','test2','test3','test4','test5'];
console.log('length - '+test.length);
for ( var k = 0, len = test.length; k < len; k++ ) {
var tests = test.pop();
console.log(tests+' - '+k);
}Or with a while loop:
var test = ['test1','test2','test3','test4','test5'];
console.log('length - '+test.length);
var k = 0;
while (test.length) {
var tests = test.pop();
console.log(tests+' - '+(k++));
}You're increasing k each time. After printing 2, k == 3 while there are still 2 elements left in the list. But since k > test.length, the loop ends.
If you really still want to keep count, increase k but don't test it:
var test = ['test1', 'test2', 'test3', 'test4', 'test5'];
console.log('length - ' + test.length);
for (var k = 0; test.length > 0; k++) {
var tests = test.pop();
console.log(tests + ' - ' + k);
}Consider the logic of what you're doing... you're burning your candle at both ends (so to speak).
k = 0, length = 5 ('test1') at this point test5 is thrown away (that's what pop does, it drops the last element)
k = 1, length = 4 ('test2') (at this point test4 is thrown away)
and so on... after 3 iterations your array is 3 items.
I *think what you're trying to do you would accomplish with splice
while(myArray.length > 0){
console.log(myArray[0])
myArray.splice(0,1)
}
If you like to keep your code style, just added following line. This is to prevent array length re-sizing in the for loop:
var arrSize = test.length;
Your final code would look like this:
<script>
var test = ['test1', 'test2', 'test3', 'test4', 'test5'];
var arrSize = test.length;
console.log('length - ' + arrSize);
for (var k = 0; k < arrSize; k++) {
var tests = test.pop();
console.log(tests + ' - ' + k);
}
</script>