用编程方式填充数组

Question

Here is a code to create an array of arrays named sims through a for loop and using str1 .

so far I need to define the sims length manually, equal to length of str1 like : let sims = [[],[],[],[]]; (four arrays equal to four words on str1 )

how can I fill sims with arrays programmatically?

 var str1 = "do you ever looked"; var str2 = "do you fr ever looked"; let sims = [[],[],[],[]]; // instead I want let sims = []; let s1 = str1.split(" ") let s2 = str2.split(" ") for (var j = 0; j < s1.length; j++) { for (var i = 0; i < s2.length; i++) { sims[j].push(s1[j].toString()); } } console.log(sims); 

Answer 1

You could just split , map and fill an array to accomplish the same output, no need for any for loop at that time

 var str1 = "do you ever looked"; var str2 = "do you fr ever looked"; let subArrayLength = str2.split(" ").length; let sims = str1.split(' ').map( value => new Array( subArrayLength ).fill( value ) ); console.log(sims); 

Answer 2

Here is a single line solution using just Array.from and split .

Explanation

• s1 and s2 are respectively the two strings splitted by a blankspace.
• The first array.from inherits from s1 its length, the second argument is invoked to fill all the values. For that second argument, we care about the index ( i ).
• The second array.from inherits from s2 its length, for that one we don't care about either of the arguments, since we will just need the s1 element at index i of the previous loop (so, s2.length times s1[i]). '' + is just the equivalent of toString , which is unneeded, but the main example had it, so...

 var str1 = "do you ever looked", s1 = str1.split(' '); var str2 = "do you fr ever looked", s2 = str2.split(' '); let sims = Array.from(s1, (_,i) => Array.from(s2, () => '' + s1[i])); console.log(sims); 

Answer 3

You could easily get this done by pushing empty arrays into your sims-array inside your first loop, like in the example below:

 var str1 = "do you ever looked"; var str2 = "do you fr ever looked"; let sims = []; let s1 = str1.split(" ") let s2 = str2.split(" ") for (var j = 0; j < s1.length; j++) { sims.push([]); // this does the trick :-) for (var i = 0; i < s2.length; i++) { sims[j].push(s1[j].toString()); } } console.log(sims); 

Answer 4

Do initializing the array before pushing

sims[j] = [];

 var str1 = "do you ever looked"; var str2 = "do you fr ever looked"; let sims = []; let s1 = str1.split(" ") let s2 = str2.split(" ") for (var j = 0; j < s1.length; j++) { sims[j] = []; for (var i = 0; i < s2.length; i++) { sims[j].push(s1[j].toString()); } } console.log(sims); 

Answer 5

One way :

var s1 = str1.split(" ")
let array = []
for(var i = 0; i < s1.length; s1++) array.push(new Array())