将单元素数组的Javascript数组转换为一维数组

Question

I'm stumped with this one. I have an array that looks like this:

[[1],[2],[3],[4],[5]]

(an array of single member arrays)

That array is given to me by google apps script, so I can't change the code that creates it.

i'm trying to get the index of a certain value. I can't use indexOf because each value is an array of a single member (I tried array.indexOf([3]), but that doesn't work). Is there an easy way to convert it to a 1d array like this:

[1,2,3,4,5]

I could always loop over the members of the original array, and copy it to a new array, but it seems like there should be a better way.

Answer 1

Just use map()

var newArr = data.map(function(subArr){
  return subArr[0];
})

Answer 2

You can use reduce() :

 var a = [[1],[2],[3],[4],[5]]; var b = a.reduce( function( prev, item ){ return prev.concat( item ); }, [] ); console.log(b); 

Or concat :

 var a = [[1],[2],[3],[4],[5]]; var b = Array.prototype.concat.apply([], a ); console.log(b); 

Or map :

 var a = [[1],[2],[3],[4],[5]]; var b = a.map( function(item){ return item[0]; } ); console.log(b); 

Answer 3

Found one answer, that seems simple enough, so I thought I would share it:

  var a = [[1], [2], [3], [4], [5], [6], [7]]; var b = a.map(function(value, index){return value[0];}); 

Answer 4

You can try to use map, which is similar to looping, but much cleaner:

arr.map(function(val){return val[0];});

Or filter to directly filter the value you need:

var num = 1;
arr.filter(function(val){return val[0] == num;});

Answer 5

这是一个可以做的班轮：

array.toString().split(',').map(Number);