javascript - Convert array of arrays to string? - Stack Overflow

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Given an array of arrays with 2 vals such :

var arrayStd = [["G14",18],["G16",17],["G16",17],["G13",17]];

I currently use this or variations of this :

var arrayStd = [["G14",18],["G16",17],["G16",17],["G13",17]];

var arrayToString = function(array){ 
  var str;
  array.map(function(a) {
    var item = a[0]+":"+a[1];
    str = str? str+'; '+item : item;
    } 
  );
return str
}
var str = arrayToString(arrayStd);
console.log(JSON.stringify(str));

Given an array of arrays with 2 vals such :

var arrayStd = [["G14",18],["G16",17],["G16",17],["G13",17]];

I currently use this or variations of this :

var arrayStd = [["G14",18],["G16",17],["G16",17],["G13",17]];

var arrayToString = function(array){ 
  var str;
  array.map(function(a) {
    var item = a[0]+":"+a[1];
    str = str? str+'; '+item : item;
    } 
  );
return str
}
var str = arrayToString(arrayStd);
console.log(JSON.stringify(str));

Or

var arrayStd = [["G14",18],["G16",17],["G16",17],["G13",17]];

var arrayToString = function(array){ 
  return str =  JSON.stringify(array).replace(/\"|\[\[|\]\]/g , "").replace(/\],\[/g , "; ").replace(/,/g , ":");
}
var str = arrayToString(arrayStd);
console.log(JSON.stringify(str));

Is there a slicker way to do obtain str= "G14:18; G16:17; G16:17; G13:17"

• javascript
• arrays
• string

Share Improve this question Follow edited May 4, 2018 at 13:02 Mohammad Usman 39.4k2020 gold badges9898 silver badges9999 bronze badges asked May 4, 2018 at 12:34 Hugo LOPEZHugo LOPEZ 61511 gold badge88 silver badges2121 bronze badges 5

• 3 really no reason to use stringify, join("; ") will do it [["G14",18],["G16",17],["G16",17],["G13",17]].map(i=>i.join(':')).join('; ') – epascarello Commented May 4, 2018 at 12:36
• 4 I'm voting to close this question as off-topic because it seems like a better fit for codereview.stackexchange. – epascarello Commented May 4, 2018 at 12:36
• let str = arrayStd.map(e => e.join(':')).join(';'); – baao Commented May 4, 2018 at 12:37
• Seems return str = array.join("; ").replace(/,/g,":") would do :D – Hugo LOPEZ Commented May 4, 2018 at 12:38
• "Is there a slicker way to do" No. That's perfect. – D. Pardal Commented May 4, 2018 at 12:39

Add a ment  | 

5 Answers 5

Sorted by: Reset to default 4

You can use .map() and .join() like this:

let str = arrayStd.map(a => a.join(":")).join("; ");

Demo:

let arrayStd = [["G14", 18], ["G16", 17], ["G16", 17], ["G13", 17]];

let str = arrayStd.map(a => a.join(":")).join("; ");

console.log(str);

Making incremental improvements to your code...

You should be using .forEach() instead of .map() since you're not returning anything.

var arrayStd = [
  ["G14", 18],
  ["G16", 17],
  ["G16", 17],
  ["G13", 17]
];

var arrayToString = function(array) {
  var str = "";
  array.forEach(function(a) {
    var item = a[0] + ":" + a[1];
    str = str ? str + '; ' + item : item;
  });
  return str
}
var str = arrayToString(arrayStd);
console.log(JSON.stringify(str));

---

However, .map() is actually useful here to map each inner array to a string, then take the new array of strings and join them.

var arrayStd = [
  ["G14", 18],
  ["G16", 17],
  ["G16", 17],
  ["G13", 17]
];

var arrayToString = function(array) {
  var str = array.map(function(a) {
    return a[0] + ":" + a[1];
  }).join("; ");

  return str
}
var str = arrayToString(arrayStd);
console.log(JSON.stringify(str));

---

You can also use .join() on the inner array, and can get rid of the str variable by returning the result immediately.

var arrayStd = [
  ["G14", 18],
  ["G16", 17],
  ["G16", 17],
  ["G13", 17]
];

var arrayToString = function(array) {
  return array.map(function(a) {
    return a.join(":");
  }).join("; ");
}
var str = arrayToString(arrayStd);
console.log(JSON.stringify(str));

---

Finally, in modern environments, you can convert your functions to "arrow functions" to get a more concise syntax.

const arrayStd = [
  ["G14", 18],
  ["G16", 17],
  ["G16", 17],
  ["G13", 17]
];

const arrayToString = array => array.map(a => a.join(":")).join("; ")

var str = arrayToString(arrayStd);
console.log(JSON.stringify(str));

I also changed var to const, which is a good idea for variables you won't modify.

Highly inspired by previous suggestions, yet shorter and more readable than others :

var arrayStd = [["G14",18],["G16",17],["G16",17],["G13",17]];

var arrayToString = function(array){ 
  return array.join("; ").replace(/,/g,":")
}
console.log(arrayToString(arrayStd));

You can use map function, and join the resulting array.

let arrayStd = [["G14",18],["G16",17],["G16",17],["G13",17]];
//"G14:18; G16:17; G16:17; G13:17"

let arrayNew = arrayStd.map((elem,i) => `${i!==0?'; ':''}${elem[0]}:${elem[1]}`).join("");
console.log(arrayNew);

let arrayStd = [["G14",18],["G16",17],["G16",17],["G13",17]];
//"G14:18; G16:17; G16:17; G13:17"

let arrayNew = arrayStd.map((elem,i) => `${i!==0?'; 
':''}${elem[0]}:${elem[1]}`).join("");
console.log(arrayNew);

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