Iterating through a JSON array and returning a subset of elements-CodePudding

I'm new to JS and trying to figure out how to iterate through a json array and return only a subset of elements. Specifically I would like to know how to return only the 'first_name' and 'last_name' from the Mock data in the attached code snippet. It seems like it should be straightforward but I'm scratching my head.

let people =  [{"id":1,"first_name":"Talbert","last_name":"Kohnert","email":"[email protected]","country":"Indonesia"},
{"id":2,"first_name":"Ruthie","last_name":"McKleod","email":"[email protected]","country":"Sweden"},
{"id":3,"first_name":"Lenore","last_name":"Foister","email":"[email protected]","country":"Nicaragua"}]

people.forEach(person => {
    for (let key in person) {
        console.log(`${key} => ${person[key]}`);
    }

CodePudding user response：

Use the element names

people.forEach(person => {
  console.log(JSON.stringify(person)   "\n");
  console.log(person["first_name"], person["last_name"], "\n");
});

Produces this output:

{"id":1,"first_name":"Talbert","last_name":"Kohnert","email":"[email protected]","country":"Indonesia"}
Talbert Kohnert 


{"id":2,"first_name":"Ruthie","last_name":"McKleod","email":"[email protected]","country":"Sweden"}
Ruthie McKleod 

{"id":3,"first_name":"Lenore","last_name":"Foister","email":"[email protected]","country":"Nicaragua"}
Lenore Foister

CodePudding user response：

you can achieve this by using the map function.
map lets you iterate over each item in the array and return a new value for each iteration while returning a new array, so for your case:

let people =  [
 {"id":1,"first_name":"Talbert","last_name":"Kohnert","email":"[email protected]","country":"Indonesia"},
 {"id":2,"first_name":"Ruthie","last_name":"McKleod","email":"[email protected]","country":"Sweden"},
 {"id":3,"first_name":"Lenore","last_name":"Foister","email":"[email protected]","country":"Nicaragua"}
]

const newArray = people.map((person) => {
  return {
   first_name: person.first_name,
   last_name: person.last_name
  }
})

console.log(newArray)

here you get a new array with just the properties you need.

CodePudding user response：

There are numerous way of achieving this output. One of most frequently used method is using map() of es6.

let people =  [{"id":1,"first_name":"Talbert","last_name":"Kohnert","email":"[email protected]","country":"Indonesia"},
{"id":2,"first_name":"Ruthie","last_name":"McKleod","email":"[email protected]","country":"Sweden"},
{"id":3,"first_name":"Lenore","last_name":"Foister","email":"[email protected]","country":"Nicaragua"}]

//by map method
people.map((person,index)=>{
     console.log(`${person.first_name} ${person.last_name}`)
})

// by forEach
people.forEach(person => {
        console.log(`${person.first_name} ${person.last_name}`)
}