计算内部二维数组的值 - javascript
[英]Count values of the inner two-dimensional array - javascript
问题描述
I have a two-dimensional array.
我有一个二维数组。 I'm trying to count the values within the inner array.我正在尝试计算内部数组中的值。 I'm aware of JS array.length .我知道 JS array.length 。 But doing testData.length yields 5. Which is accurate.但是做testData.length会产生 5。这是准确的。 However, I want to count the number of items within each sub array.但是，我想计算每个子数组中的项目数。
testData[0].length would yield 6. But how would I dynamically count through each sub array? testData[0].length将产生 6。但是我将如何动态计算每个子数组？ (as it will change). （因为它会改变）。
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"]
]
4 个解决方案
解决方案1
11 2018-01-26 21:27:57
Use reduce :使用reduce ：
ES6: ES6：
const count = testData.reduce((currentCount, row) => currentCount + row.length, 0);
ES5: 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文档： https ://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce
解决方案2
5 2013-05-09 18:09:52
Use Array.forEach使用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另请参阅： https ://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/forEach
解决方案3
0 已采纳 2013-05-09 18:07:18
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]);
}
}
解决方案4
0 2013-05-09 18:17:52
Try adding a new property to the Array object.尝试向 Array 对象添加新属性。
<!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>
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