I want to get length of every element in array
my code is
var a = "Hello world" ;
var chars = a.split(' ');
so I will have an array of
chars = ['Hello' , 'world'] ;
but how I can get length of each word like this ?
Hello = 5
world = 5
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6 Answers
You can use map Array function:
var lengths = chars.map(function(word){
return word.length
})
Comments
ES6 is now widely available (2019-10-03) so for completeness — you can use the arrow operator with .map()
var words = [ "Hello", "World", "I", "am", "here" ];
words.map(w => w.length);
> Array [ 5, 5, 1, 2, 4 ]
or, very succinctly
"Hello World I am here".split(' ').map(w => w.length)
> Array [ 5, 5, 1, 2, 4 ]
4 Comments
friedi
Or you can do it with array comprehension:
[for (word of words) word.length]
Cristofayre
I'm lost! OK, so "words" is an array, and "words.map" gets the length of each word, which it stored in an array as "> Array[5,5,1,2,4]. But how to access the cells of that latter array? What is it's name?
Stephen P
@Cristofayre - in my answer the examples are from typing in the browser console, and I'm not assigning the result of
words.map to anything. You would want to do something like let wordLengths = words.map(w => w.length); then you an access the latter array as wordLengths[i] just like any other array. In the browser console I use var but in actual js code I never use it; I use const and let.The key here is to use .length property of a string:
for (var i=0;i<chars.length;i++){
console.log(chars[i].length);
}
Comments
You could create a results object (so you have the key, "hello", and the length, 5):
function getLengthOfWords(str) {
var results = {};
var chars = str.split(' ');
chars.forEach(function(item) {
results[item] = item.length;
});
return results;
}
getLengthOfWords("Hello world"); // {'hello': 5, 'world': 5}
Comments
You can use forEach, if you want to keep the words, and the length you can do it like this:
var a = "Hello world" ;
var chars = a.split(' ');
var words = [];
chars.forEach(function(str) {
words.push([str, str.length]);
});
You can then access both the size and the word in the array.
Optionally you could have a little POJO object, for easier access:
var a = "Hello world" ;
var chars = a.split(' ');
var words = [];
chars.forEach(function(str) {
words.push({word: str, length: str.length});
});
Then you can access them like:
console.log(words[0].length); //5
console.log(words[0].word); //"Hello"
Or using map to get the same POJO:
var words = chars.map(function(str) {
return {word: str, length: str.length};
});
