拆分字符串数组后未定义(JavaScript)
我希望将字符串数组(拆分字符串数组后未定义(JavaScript),javascript,parsing,split,nan,parsefloat,Javascript,Parsing,Split,Nan,Parsefloat,我希望将字符串数组(objData)拆分为单个元素,并将它们复制到二维数组(sequence)的第一行。请参阅下面的代码 for(i = 0; i < objData.length; i++) { console.log("objData[i]: " + objData[i]); parts = objData[i].split(' '); sequence[0][n] = parts[1]; console.log("sequence[0][n]: " +
objData
)拆分为单个元素,并将它们复制到二维数组(sequence
)的第一行。请参阅下面的代码
for(i = 0; i < objData.length; i++)
{
console.log("objData[i]: " + objData[i]);
parts = objData[i].split(' ');
sequence[0][n] = parts[1];
console.log("sequence[0][n]: " + sequence[0][n]);
sequence[0][n+1] = parts[2];
sequence[0][n+2] = parts[3];
n+=3;
parts = [];
}
我希望使用空格作为分隔符拆分这些字符串(来自objData
的每个元素),并将十进制值复制到序列的第一行。我还想将这些字符串值解析为浮点值
使用上面的代码将复制值,但是序列第一行的内容如下所示:
[2.11733NaN, 0.0204144NaN, 1.0852NaN, 2.12303undefined, 0.0131256undefined ..... etc.]
其余的元素都附加了“undefined”,如图所示
我尝试使用以下行解析为浮点:
parts = objData[i].split(' ').map(parseFloat);
然而,序列
的内容是:
[2.11733, 0.0204144, 1.0852, NaN, NaN ..... etc.]
如果有人能告诉我如何分割和解析这些数据,我将不胜感激!谢谢。在我看来,你的工作很繁重
让我们一步一步来:
// Make sure sequence array is empty
sequence = [];
// We want to process each element of the objData array :
objData.forEach (function (obj_n) {
// First split the element, one or more spaces separate fields
obj_n = obj_n.split (/ +/); // obj_n is now an array
// Extract elements 1 to 3
obj_n = obj_n.slice (1, 4); // obj_n is now the three data values
// Append the three elements to the sequence array:
sequence = sequence.concat (obj_n);
});
// Now convert to numbers:
sequence = sequence.map (function (f) { return +f });
更紧凑地说:
sequence = [];
objData.forEach (function (obj_n) {
sequence = sequence.concat (obj_n.split (/ +/).slice (1, 4));
});
sequence = sequence.map (function (f) { return +f });
回答以下o.p.评论中的其他限制
function parseObjData (objData, m, n) { // Add n items to sequence m
if (!sequence[m]) // make sure sequence[m] exists
sequence[m] = [];
objData.forEach (function (obj_n) {
sequence[m] = sequence[m].concat (obj_n.split (/ +/).
slice (1, n + 1));
});
sequence[m] = sequence[m].map (function (f) { return +f });
}
感谢您提供简洁的代码和解释。这是函数的一部分,该函数以objData
为参数,以整数m
递增序列的行。为了对objData
进行同样的分析并将其分配给序列的每一行,该代码是否也可以应用于该行?例如,我如何实现这个等价物:sequence[m][]=sequence[m][].concat(obj_n.split(+/+/).slice(1,4))代码>?
function parseObjData (objData, m, n) { // Add n items to sequence m
if (!sequence[m]) // make sure sequence[m] exists
sequence[m] = [];
objData.forEach (function (obj_n) {
sequence[m] = sequence[m].concat (obj_n.split (/ +/).
slice (1, n + 1));
});
sequence[m] = sequence[m].map (function (f) { return +f });
}