I am trying to decrement a for/in loop in js.
I have found lots of instruction on decrementing a for-loop, but had no luck finding a statement that decrements a for/in loop.
var classRegister = ["Lawrence", "John", "Jeff", "Bobbi"];
for( var index in classRegister ) {
console.log(classRegister[index]);
}This is my incrementing for/in loop statement that I want to modify to decrement.
Use basic for loop & avoid for..in to iterate an array
var classRegister = ["Lawrence", "John", "Jeff", "Bobbi"];
for (let i = classRegister.length - 1; i >= 0; i--) {
console.log(classRegister[i]);
}
i instead of i >= 0
If you want to use for/in you can, you simply need to subtract your index from the last index value.
var classRegister = ["Lawrence", "John", "Jeff", "Bobbi"];
for( var index in classRegister ) {
console.log(classRegister[classRegister.length - 1 - index]);
}
You should not use for..in for arrays instead use simple loop
var classRegister = ["Lawrence", "John", "Jeff", "Bobbi"];
for(let index = classRegister.length-1; index >= 0; index-- ) {
console.log(classRegister[index]);
}Or a while loop
var classRegister = ["Lawrence", "John", "Jeff", "Bobbi"];
let index = classRegister.length-1;
while(index >= 0) {
console.log(classRegister[index]);
index--;
}There are hacky ways to do but you should never use them IMO
var classRegister = ["Lawrence", "John", "Jeff", "Bobbi"];
let copy = [...classRegister].reverse() // this reverse array in place
for( var index in copy ) {
console.log(copy[index]);
}
while(index--) and avoid that index--; in the while... I think my brain is 'falsey" tonight also :)