I have a two-dimensional array. I'm trying to count the values within the inner array. I'm aware of JS array.length. But doing testData.length yields 5. Which is accurate. However, I want to count the number of items within each sub array.
testData[0].length would yield 6. But how would I dynamically count through each sub array? (as it will change).
var testData = [["column1","test1","test1","tea","party", "water bottle"],
["column2","test2","test2","test2 test2"],
["column3","test2","test2","test2 test2 "],
["column4","test2","test2 test2f asdfsdf"],
["column5","test2","test2 test2f asdfsdfasdfasdfasa asda asdfsas"]
]
I have a two-dimensional array. I'm trying to count the values within the inner array. I'm aware of JS array.length. But doing testData.length yields 5. Which is accurate. However, I want to count the number of items within each sub array.
testData[0].length would yield 6. But how would I dynamically count through each sub array? (as it will change).
var testData = [["column1","test1","test1","tea","party", "water bottle"],
["column2","test2","test2","test2 test2"],
["column3","test2","test2","test2 test2 "],
["column4","test2","test2 test2f asdfsdf"],
["column5","test2","test2 test2f asdfsdfasdfasdfasa asda asdfsas"]
]
5 Answers
Reset to default 12Use reduce:
ES6:
const count = testData.reduce((currentCount, row) => currentCount + row.length, 0);
ES5:
var count = testData.reduce(function(currentCount, row) {
return currentCount + row.length;
}, 0);
Documentation : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce
Use Array.forEach
s=0;
testData.forEach(function(e,i,a){s += e.length; });
See also: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/forEach
var testData = [
["column1","test1","test1","tea","party", "water bottle"],
["column2","test2","test2","test2 test2"],
["column3","test2","test2","test2 test2 "],
["column4","test2","test2 test2f asdfsdf"],
["column5","test2","test2 test2f asdfsdfasdfasdfasa asda asdfsas"]
];
for(var i=0;i < testData.length;i++){
for(var j=0;j<testData[i].length;j++){
alert(testData[i][j]);
}
}
Try adding a new property to the Array object.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=windows-1250">
<title>New Property</title>
<script type="text/javascript" language="JavaScript">
Array.prototype.biLength = function(){
numItems = 0;
numRows = this.length;
for (var i = 0; i < numRows; i++){
row = testData[i];
numCols = row.length;
for (var j = 0; j < numCols; j++){
numItems++;
}
}
return numItems;
};
var testData = [
["column1","test1","test1","tea","party", "water bottle"],
["column2","test2","test2","test2 test2"],
["column3","test2","test2","test2 test2 "],
["column4","test2","test2 test2f asdfsdf"],
["column5","test2","test2 test2f asdfsdfasdfasdfasa asda asdfsas"]
];
alert(testData.biLength());
</script>
</head>
<body>
</body>
</html>
var lengths = testData.map(subArray => subArray.length);
console.log(lengths);