get character after space of array value on javascript

user_6813148 0
Viewed 429

i have question about getting character of string after space where the string is value of array like this..

arr = ['aaa: 2' , 'aaa: 5', 'aaa: 6', 3 , 7 , 8];

output = arr.filter(function (p) {
            if (!Number(p)) {  // get string value 
               return p.includes('aaa').split(' ').pop();
            }
         });

console.log(output)

i got error "TypeError: p.includes(...).split is not a function"

if i remove the .split(' ').pop();

array['aaa: 2','aaa: 5','aaa: 6']

i just want the output like this

array [2,5,6]

can anyone who's have experience on same problem help me? i'm stuck. thank you guys...

vue.js javascript
9 Answers

  1. String.prototype.includes() return bool value, which has no method split

  2. Array.prototype.filter() takes:

Function is a predicate, to test each element of the array. Return true to keep the element, false otherwise.

  1. For your task you need to additionally use Array.prototype.map()

const arr = ['aaa: 2', 'aaa: 5', 'aaa: 6', 3, 7, 8];

const output = arr
    .filter((p) => {
        return Number(p) ? false : p.includes('aaa');
    })
    .map((p) => Number(p.split(' ').pop()));

console.log(output);

user_84391230

Array.prototype.filter() function is intended to only filter an array, without modifications. To combine modifications and filetring use reduce instead:

const arr = ['aaa: 2' , 'aaa: 5', 'aaa: 6', 3 , 7 , 8];

const output = arr.reduce((result, current) => {
            if (!Number(current)) {  // get string value  
               if(current.includes('aaa')) {
               return [...result, current.split(' ').pop()];
               }
            }
            return result
         }, []);

console.log(output)

user_129984280

Firstly, .filter is the wrong method to use here, it either expects a true or false to keep/remove the given item from the array. Use .map instead.

Secondly, .includes returns true or false so trying to split a boolean will not work

if you want to remove the numbers as mentioned in your last edit, filter first. Try this:

// first filter out numbers
const output = arr.filter(function(p) {
    return !Number(p)
}

// then get the numbers out
output = output.map(function(p) {
    if (p.includes('aaa')) { 
        return Number(p.split(' ').pop());
    }
});
user_51081580
  1. filter method return only conditionally some filtered values of the array.
  2. includes method return boolean type value. So you can't use split method with a boolean type value.

if you want to get a customize array from your main array then you can use reduce method.

const arr = ['aaa: 2', 'aaa: 5', 'aaa: 6', 3, 7, 8];

const output = arr.reduce((value, key) => {
  if (!Number(key) && key.includes('aaa')) {
    value.push(parseInt(key.split(' ').pop()));
  }
  return value;
}, []);

console.log(output);

user_97094050

You can use .reduce: 

const arr = ['aaa: 2' , 'aaa: 5', 'aaa: 6', 3 , 7 , 8];

const output = arr.reduce((acc, arrayValue) => {

    const [key, value] = arrayValue.toString().split(': ');

    if (key.includes('aaa')) {
      acc.push(parseInt(value))
    }
    
    return acc;
    }, []);

console.log(output)

user_29083300

Creating a regex that groups the number, and then extracting it would work.

const regex = /aaa:\s(\d+)/
const matches = regex.exec(p)
return matches && matches.length > 0 && matches[0]
user_82180100

Looks like you need the numbers from the array? Use Array.map and a bit of RegEx magic:

console.log(
  JSON.stringify( ['aaa: 2', 'aaa: 5', 'aaa: 6', 3 , 7 , 8]
    .map( v => /:\s+\d$/.test(v) ? Number(v.split(": ")[1]) : v) ) );
 
// only numbers from strings?
console.log(
  JSON.stringify( ['aaa: 2', 'aaa: 5', 'aaa: 6', 3 , 7 , 8]
   .filter( v => isNaN(+v) )
   .map( v => Number( v.split(": ")[1] ) ) ) );

NICon_581860

Ciao, try this:

var arr = ['aaa: 2' , 'aaa: 5', 'aaa: 6', 3 , 7 , 8];

console.log(arr.map(el => {
   if(typeof el === "string") {
      return parseInt(el.split(": ")[1]);
   }
}).filter(el => el!== undefined))

user_138970650

If the value is a string, you can use the following regular expression to extract the digit following the space e.g.

/^\w+:\s(\d+)$/

Match group #1 will be the digit, you will just need to parse it to an integer.

const transform = (arr) =>
  arr.map(val => typeof val === 'string'
    ? parseInt(val.match(/^\w+:\s(\d+)$/)[1], 10)
    : val)

console.log(transform(['aaa: 2' , 'aaa: 5', 'aaa: 6', 3 , 7 , 8]))

user_17622240
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