How to write a regular expression to scan whether input is a signed decimal or not?
如何编写正则表达式来扫描输入是否为带符号的小数？
e.g:
例如：
-1.234567
-.1234567
123456789
1.2345678
1234567.8
-1234.567
Input length must be 9.
输入长度必须为9。
2 个解决方案
#1
2
Why are you using RegEx? There are better methods to determine if a string is signed or not.
你为什么使用RegEx？有更好的方法来确定字符串是否已签名。
Use decimal.TryParse() and Math.Sign() to get your answer.
使用decimal.TryParse（）和Math.Sign（）来获得答案。
string input = "-1.2342";
decimal decValue;
bool isDecimal = decimal.TryParse(input, out decValue);
if (isDecimal)
{
int signValue = Math.Sign(decValue);
}
else
{
throw new Exception("Not a valid decimal!");
}
#2
0
You could do it the hard way:
你可以这么做：
([-\d]\d\.\d\d\d\d\d\d|[-\d]\d\d\.\d\d\d\d\d|[-\d]\d\d.\d\d\d\d|...)
Basically this is any of the forms you listed OR-ed. This is quite tedious, but right now I can't think of any other way that will work for all possible inputs.
基本上这是您列出的任何形式的OR-ed。这是相当繁琐的，但是现在我想不出任何其他适用于所有可能输入的方式。
#1
2
Why are you using RegEx? There are better methods to determine if a string is signed or not.
你为什么使用RegEx？有更好的方法来确定字符串是否已签名。
Use decimal.TryParse() and Math.Sign() to get your answer.
使用decimal.TryParse（）和Math.Sign（）来获得答案。
string input = "-1.2342";
decimal decValue;
bool isDecimal = decimal.TryParse(input, out decValue);
if (isDecimal)
{
int signValue = Math.Sign(decValue);
}
else
{
throw new Exception("Not a valid decimal!");
}
#2
0
You could do it the hard way:
你可以这么做：
([-\d]\d\.\d\d\d\d\d\d|[-\d]\d\d\.\d\d\d\d\d|[-\d]\d\d.\d\d\d\d|...)
Basically this is any of the forms you listed OR-ed. This is quite tedious, but right now I can't think of any other way that will work for all possible inputs.
基本上这是您列出的任何形式的OR-ed。这是相当繁琐的，但是现在我想不出任何其他适用于所有可能输入的方式。