splitting an array
I have an array of comma separated values like var myArray = [0,1,0,1,0,0,0,0,1]
I want to split it based on a count if count is 3 I want to end up with three arrays like
var myArrayA = [0,1,0];
var myArrayB = [1,0,0];
var myArrayC = [0,0,1];
I need to treat it as a 3x3 matrix and do开发者_开发技巧 a transpose.
array.slice would be my suggestion
in your SPECIFIC situation have a look at this
<script>
function getMatrix(arr,count) {
var res = {};
for (var i=0;i<arr.length;i+=count) {
res[i]=arr.slice(i,(i+count));
}
return res;
}
var result = getMatrix("0,1,0,1,0,0,0,0,1".split(","),3);
for (var o in result) alert(result[o]);
</script>
Try array.slice(start, end)
Example:-
var firstArray = array.slice(0,count);
var secondArray = array.slice(count);
Fun! The only thing you need to know really is that to transpose, set m(i,j) = m(j,i) forall (i,j) in the matrix. I ended up converting to a matrix representation, which is less concise but mor legible...
var a = [1,2,3,4,5,6];
function listToSquareMatrix(a,colDim) {
a = a.slice(0);
var res = [];
var row = 0;
var col;
for(; a.length; row++) {
for(col = 0; col < colDim; col++) {
res.push({
row : row,
col : col,
val : a.shift()
});
}
}
return res;
}
function transpose(m) {
for(var i=0; i < m.length; i++) {
var v = m[i];
var row = v.row;
v.row = v.col;
v.col = row;
}
return m.sort(function (a,b) { var r = compare(a.row,b.row); var c = compare(a.col,b.col); return r !== 0 ? r : c });
}
function compare(a,b) {
if (a < b) {
return -1;
} else if (b < a) {
return 1;
}
return 0;
}
function matrixToArray(m) {
var res = [];
for (var i = 0; i < m.length; i++) {
res.push(m[i].val);
}
return res;
}
console.log(listToSquareMatrix(a, 3));
console.log(matrixToArray(transpose(listToSquareMatrix(a, 3))));
console.log(matrixToArray(transpose(transpose(listToSquareMatrix(a, 3)))));
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