How to remove specific array elements from foreach loop in javascript

Question

var fruit = ["apple","pear","pear","pear","banana"]; 

How to remove all "pear" fruits from this array?
I tried the following, but one pear still remains:

 for(var f in fruit) { if ( fruit[f] == "pear" ) { fruit.splice(f, 1); } } for(var f in fruit) { document.write(fruit[f]+"<br>"); } 

Outputs:

 apple pear banana 

What am I doing wrong? Demo version: http://jsfiddle.net/SbxHc/

Answer 1

 var fruit = ["apple", "pear", "pear", "pear", "banana"], i; for (i = 0; i < fruit.length; ++i) { if (fruit[i] === "pear") { fruit.splice(i--, 1); } } console.log(fruit); //["apple", "banana"] 

Answer 2

 for (var i = fruit.length - 1; i > -1; i--) { if (fruit[i] == "pear") fruit.splice(i, 1); } 

Answer 3

When you delete elements from an array when it moves through it, you usually repeat backward so that the current index does not skip elements when they are deleted:

 var fruit = ["apple","pear","pear","pear","banana"]; var i; for (i = fruit .length - 1; i >= 0; i--) { if (fruit [i] === "pear") { fruit .splice(i, 1); } } console.log(fruit ); 

Answer 4

If there are a lot of “wrong” elements in the original array, I suggest at least not using the in-place array, but collecting all the “correct” elements into a new array:

 var rightFruits = []; for (var i = 0, len = fruit.length; i < len; ++i) { if (fruit[i] !== 'pear') { rightFruits.push(fruit[i]); } } 

Answer 5

 var i; for (i = 0; i < fruits.length; i += 1) { if (fruits[i] == "pear") { fruits.splice(i, 1); i -= 1; } } 

6.4. Listing

Because JavaScript arrays are really objects, the for in operator can be used to iterate over all the properties of the array. Unfortunately, for in makes no guarantees about the order of properties, and most arrays expect elements to be created in numerical order. In addition, there is still a problem with unexpected properties being unloaded from the prototype circuit.

Fortunately, the usual approval problem resolves these issues. JavaScript for the operator is similar to that in most C-like languages. It is controlled by three sentences: the first initializes the loop, the second is the while condition, and the third is incremented:

 var i; for (i = 0; i < myArray.length; i += 1) { document.writeln(myArray[i]); } 

Answer 6

 var i; while ((i = fruit.indexOf("pear")) > -1) fruit.splice(i,1); 

Remember that Array.indexOf is not supported by IE8 and below. -_-

Answer 7

Why not iterate over the list? Thus, when you remove an item from the list and change the length, it does not violate the loop logic:

 var fruit = ["apple","pear","pear","pear","banana"]; for (var i = fruit.length - 1; i >= 0; i--) { if (fruit[i] === "pear") { fruit.splice(i, 1); } } console.log(fruit); // ["apple", "banana"] 

Answer 8

If he doesn't want to repeat the iteration, you can use a combination of while and pop-function of the array

 var daltons = [ { id: 1, name: "Joe" }, { id: 2, name: "William" }, { id: 3, name: "Jack" }, { id: 4, name: "Averell" } ]; var dalton; while (dalton=daltons.pop()) { console.log(dalton.name); } console.log(daltons); 

Answer 9

You can also use filter :

 let noPears = fruits.filter(fruit => fruit != 'pear') 

Answer 10

 for(var f in fruit) { if ( fruit[f] == "pear" ) { fruit.splice(f-1, 1); } } for(var f in fruit) { document.write(fruit[f]+"<br>"); } 

to use