Javascript 基于两个条件退出 While 循环
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Exit a While loop based on two conditions
提问by user3357963
I have a question relating to the answer on this post Javascript code to parse CSV data
我有一个关于这篇文章的答案的问题Javascript code to parse CSV data
I'm finding I get an extra "\r\n" on the end which I don't want to add to the array. I've tried to break out of the while loop...
我发现最后有一个额外的“\r\n”，我不想将其添加到数组中。我试图摆脱 while 循环......
The original working line is
原来的工作线是
while (arrMatches = objPattern.exec( strData )){
but I need to break out if arrMatches = "\r\n"
但如果 arrMatches = "\r\n" 我需要爆发
while ((arrMatches[ 1 ] != "\r\n") && arrMatches = objPattern.exec( strData )){
but get an Invalid left-hand side in assignmenterror.
但得到一个Invalid left-hand side in assignment错误。
What is the correct syntax?
什么是正确的语法？
采纳答案by dbf
This approach should work, the only thing is that arrMatches should be between ( )too, to avoid arrMatchesbeing set to true from the second condition.
这种方法应该有效，唯一的问题是 arrMatches 也应该介于两者之间( )，以避免arrMatches从第二个条件设置为 true。
while ((arrMatches = objPattern.exec( strData )) && (arrMatches[ 1 ] != "\r\n")) {
回答by zeacuss
just separate the two conditions to make it more readable and understandable
只需将两个条件分开，使其更具可读性和可理解性
while(arrMatches = objPattern.exec( strData )){
if(arrMatches[ 1 ] == "\r\n"){
break;
}
/*
*if(arrMatches[ 1 ] == "\r\n")
* break;
*/
// rest of code
}
回答by Arman McHitarian
Another way: the expression block of the whileoperator can be easily split up into a chain of comma-separated expressions expecting the loop to break once the last expression evaluates to 0/false.
另一种方式：while运算符的表达式块可以很容易地分成一串逗号分隔的表达式，一旦最后一个表达式的计算结果为 0/false，循环就会中断。
It's NOT equivalent to logical && chainingsince a comma ','operators in JS always return the last expression. (Thanks GitaarLab to remind me about that)
它不等同于逻辑 && 链接，因为','JS 中的逗号运算符总是返回最后一个表达式。（感谢 GitaarLab 提醒我这一点）
In these examples the loop stops once the last variable reaches 0 and thus evaluates to false.
在这些示例中，一旦最后一个变量达到 0，循环就会停止，因此计算结果为 false。
var i = 10, j = 10;
while (i--, j--) console.log(i);
/*9
8
7
6
5
4
3
2
1
0*/
var i = 10, j = 5;
while (i--, j--) console.log(i);
/*9
8
7
6
5*/
var i = 10, j = 5, k = 3;
while (i--, j--, k--) console.log(i);
/*9
8
7*/
回答by aug
You could try a whileloop that handles one condition, and inside the whileloop, you have an ifstatement that checks the other condition.
您可以尝试while处理一个条件的while循环，并且在循环内部，您有一个if检查另一个条件的语句。
Example:
例子：
while (one condition) {
if (other condition) {
do something;
}
}
Whether this is the appropriate way to do it, I'm not entirely sure. I'll update my answer if I find something better.
这是否是适当的方法，我不完全确定。如果我找到更好的答案，我会更新我的答案。
回答by lleite
Try: while ((arrMatches[ 1 ] != "\r\n") && arrMatches == objPattern.exec( strData )){
尝试： while ((arrMatches[ 1 ] != "\r\n") && arrMatches == objPattern.exec( strData )){
With a single '=', you are actually assigning a value to arrMatches. In order to compare values you should use ==.
使用单个 '='，您实际上是在为arrMatches分配一个值。为了比较值，您应该使用==。
