how to pick some value from an object {} and put it into an array []-CodePudding

got some information from an API and now want to pick "correct_answer" property from all of them and then make an array from correct_answer here is the API information :

apipresave=[
  {question: "What does the &quot;MP&quot; stand for in MP3?",
   correct_answer: "Moving Picture",
   incorrect_answers: ["Music Player", "Multi Pass", "Micro Point"]},

  {question: "What does GHz stand for?", 
   correct_answer: "Gigahertz", 
   incorrect_answers: ["Gigahotz", "Gigahetz", "Gigahatz"]}, 

  {question: "In the programming language Java, which of these keywords would you put on a variable 
   to make sure it doesn&#039;t get modified?", 
   correct_answer: "Final", 
   incorrect_answers: ["Static", "Private", "Public"]},
]

btw I have already put this information on a const and have full access to them in code I have tried to loop over them and use push to get them but it didn't work I put it below :

   //puting all correct_answer  into an array 
   function correct_answer_array_func (){
         const correct_answer_array =[]
         for(let i =0 ; i<4;i  ){
             correct_answer_array.push(apipresave[i].correct_answer) 
                 return correct_answer_array
         }    
    }

so how to obtain "correct_answer" from all the objects and put them in an array
the final result will be :

 correct_answer_array  =["Moving Picture","Gigahertz","Final"]  // correct_answer values

CodePudding user response：

You're looking for the .map() Javascript Array method

Here is an example that should give you the array of values you are looking for.

const correct_answer_array = apipresave.map(item => item.correct_answer)
// ["Moving Picture","Gigahertz","Final"]

CodePudding user response：

To answer the question in terms of the code you provide:

In the function correct_answer_array_func you immediately return after pushing one correct_answer to the array. Also, you hardcoded the length of the array, which I believe is not the best thing to do (is the API response guaranteed to be 4 objects?)

So, to make the function work, you need something similar to:

   //puting all correct_answer  into an array 
   function correct_answer_array_func (){
         const correct_answer_array =[]
         for(let i =0 ; i<apipresave.length;i  ){
             correct_answer_array.push(apipresave[i].correct_answer) 
         }    
         return correct_answer_array
     
    }