javascript 正则表达式只允许文本框中的一个点
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/25053605/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Regex to allow only a single dot in a textbox
提问by Arjun Prajapati
I have one text input.
我有一个文本输入。
I wrote a regex for masking all special characters except .and -. Now if by mistake the user enters two .(dots) in input, then with the current regex
我写了一个正则表达式来屏蔽除.and之外的所有特殊字符-。现在，如果用户错误地在输入中输入了两个.（点），则使用当前的正则表达式
var valueTest='225..36'
valueTest.match(/[^-.\d]/)
I expected that the number will not pass this condition
我预计这个数字不会通过这个条件
How to handle this case. I just want one.(dot) in input field since it is a number.
这个案子怎么处理。我只想要输入字段中的一个.（点），因为它是一个数字。
回答by Avinash Raj
I think you mean this,
我想你是这个意思，
^-?\d+(?:\.\d+)?$
It allows positive and negative numbers with or without decimal points.
它允许带或不带小数点的正数和负数。
EXplanation:
解释：
^Asserts that we are at the start.-?Optional-symbol.\d+Matches one or more numbers.(?:start of non-capturing group.\.Matches a literal dot.\d+Matches one or more numbers.?Makes the whole non-capturing group as optional.$Asserts that we are at the end.
^断言我们处于开始阶段。-?可选-符号。\d+匹配一个或多个数字。(?:非捕获组的开始。\.匹配一个文字点。\d+匹配一个或多个数字。?使整个非捕获组成为可选的。$断言我们到了最后。
回答by Tim.Tang
if you just want to handle number ,you can try this:
如果你只是想处理 number ，你可以试试这个：
valueTest.match(/^-?\d+(\.\d+)?$/)
回答by Mena
You can probably avoid regex altogether with this case.
在这种情况下，您可能可以完全避免使用正则表达式。
For instance
例如
String[] input = { "225.36", "225..36","-225.36", "-225..36" };
for (String s : input) {
try {
Double d = Double.parseDouble(s);
System.out.printf("\"%s\" is a number.%n", s);
}
catch (NumberFormatException nfe) {
System.out.printf("\"%s\" is not a valid number.%n", s);
}
}
Output
输出
"225.36" is a number.
"225..36" is not a valid number.
"-225.36" is a number.
"-225..36" is not a valid number.
回答by Mitul
Use below reg ex it will meet your requirements.
使用下面的 reg ex 它将满足您的要求。
/^\d+(.\d+)?$/
/^\d+(.\d+)?$/
