创建多维数组，然后将每个多维数组推入另一个数组

Question

is that possible to create a multidimensional array, then push another array on each those multidimensional array ?? lets say the variable

arr = ["apple", "orange",  "Avocados", "Tomato", "Tangerine"]

and the output I want is:

 [ ["a", ["apple", "avocados"] ], [ "o", ["orange"] ], ["T", ["Tomato", "Tangering"]] ] 

the example about to create first initial to new arr multidimensional before the output, we create like this, [[ "a"],["o"],["T"]] and output i want is on above ( the box code )

then check again if that first initial same with a first initial array, push it on those 2d arrays, that is for example, but if array length for others is not same, we should create a function, to use it again late

Answer 1

I think your output is too complicated to produce. You can simplify the output format like this:

{
   "a" : ["apple", "avocados"], 
   "o": ["orange"], 
   "t": ["Tomato", "Tangering"] 
 }

You can produce output like this with ease with Lodash:

_.groupBy(["apple", "orange",  "Avocados", "Tomato", "Tangerine"], function (item) {
  return item[0].toLowerCase()
});

Or with iterate the array:

var arr = ["apple", "orange",  "Avocados", "Tomato", "Tangerine"];
var output = [];
for (var i = 0 ; i < arr.length ; i++){
  if (output[arr[i][0].toLowerCase()] == undefined)
    output[arr[i][0].toLowerCase()] = [];
  output[arr[i][0].toLowerCase()].push(arr[i]);
}

Answer 2

You could group the data by finding the array with the value or create a new array for the result set.

 var array = ["apple", "orange", "avocados", "tomato", "tangerine"], result = array.reduce((r, s) => { var temp = r.find(([c]) => c === s[0]); if (temp) { temp[1].push(s); } else { r.push([s[0], [s]]); } return r; }, []); console.log(result); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

A better structure would be to use a Map and collect all strings to the same starting letter.

 var array = ["apple", "orange", "avocados", "tomato", "tangerine"], result = Array.from( array.reduce((map, s) => map.set(s[0], [...(map.get(s[0]) || []), s]), new Map) ); console.log(result); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

Answer 3

You can reduce the array to object

 var arr = ["apple", "orange", "Avocados", "Tomato", "Tangerine"]; var output = arr.reduce(function(res, item) { if(Object.keys(res).indexOf(item.charAt(0).toLowerCase()) == -1) { res[item.charAt(0).toLowerCase()] = []; } res[item.charAt(0).toLowerCase()].push(item); return res; },{}); console.log(output); 

Answer 4

Yet another alternative using vanilla JavaScript and some functional programming:

 const input = ["apple", "orange", "Avocados", "Tomato", "Tangerine"] // (1) An unique list of lower-cased initials of all given input words // * Set gives us the unique behavior const initials = [...new Set ( input.map (([initial]) => initial.toLowerCase ()) )] const byInitial = ([initial]) => ([initial_]) => initial_.toLowerCase () == initial // (2) This groups each world by their initial // Iterates each lowered initial and filters the input by each initial // to build the groups! const grouped = initials.reduce ((o, initial) => [ ...o, // <--- this accumulates the new result with the previous one [ initial, input.filter (byInitial(initial)) ] ], []) console.log (grouped) 

Yet another approach, now using zip :

 const input = ["apple", "orange", "Avocados", "Tomato", "Tangerine"] // (1) An unique list of lower-cased initials of all given input words // * Set gives us the unique behavior const initials = [...new Set ( input.map (([initial]) => initial.toLowerCase ()) )] const byInitial = ([initial]) => ([initial_]) => initial_.toLowerCase () == initial // (2) This builds groups each world by their initial const groups = initials.map (initial => input.filter (byInitial (initial)) ) const zip = (xs, ys) => xs.map((x, i) => [x, ys[i]]) // zip builds the pairs, where each one is the initial and the group const grouped = zip (initials, groups) console.log (grouped) 

Answer 5

Using reduce , create an object with first char of each item as the key and an array of all the items which start with that char as it's value . Then call Object.entries to get the desired output:

 const arr = ["apple", "orange", "avocados", "tomato", "tangerine"], group = Object.entries(arr.reduce((a, i) => ((a[i[0]] = a[i[0]] || []).push(i), a), {})); console.log(group);