正浮点数的正则表达式

Question

例如:
10
0.1
1.23234
123.123
0.000001
1.000
.3

错误的例子:
0001.2
-12
-1.01
+2.3

编辑:标准JavaScript正则表达式.

Answer 1

试试吧

^(?:[1-9]\d*|0)?(?:\.\d+)?$

看到它在网上的Regexr

如果不需要匹配空字符串,那么您可以在正则表达式中添加长度检查

^(?=.+)(?:[1-9]\d*|0)?(?:\.\d+)?$

积极的向前看(?=.+)确保至少有1个字符

Answer 2

这将通过所有测试用例,启用多线模式:

/^(?!0\d)\d*(\.\d+)?$/mg

说明:

/^              # start of regex and match start of line
(?!0\d)         # not any number with leading zeros
\d*             # consume and match optional digits
(\.\d+)?        # followed by a decimal and some digits after, optional.
$               # match end of line
/mg             # end of regex, match multi-line, global match

RegExr: http://regexr.com？2tpd0

Answer 3

考虑正则表达式：

^[0-9]*(?:\.[0-9]*)?$

此正则表达式将匹配浮点数，例如：

 - .343
 - 0.0
 - 1.2
 - 44
 - 44.
 - 445.55
 - 56.
 - . //Only dot(.) also matches
 - empty string also matches

上面的正则表达式不会接受：

- h32.55 //Since ^ is used. So, the match must start at the beginning
   of the string or line.
- 23.64h //Since $ is used. So, the match must occur at the end of the string or before \n at the end of the line or string.

考虑正则表达式：

^[0-9]+(?:\.[0-9]+)?$

此正则表达式将匹配浮点数，例如：

 - 45
 - 45.5
 - 0.0
 - 1.2
 - 445.55

此正则表达式将不接受：

 - h32.55 //Since ^ is used. So, the match must start at the beginning
   of the string or line. 
 - 23.64h //Since $ is used. So, the match must occur at the end of the string or before \n at the end of the line or string.
 - 44. 
 - . //Only dot(.) does not matches here
 - empty string also does not matches here

纯浮点：

^(([0-9]+(?:\.[0-9]+)?)|([0-9]*(?:\.[0-9]+)?))$ 

• 您可以在此处查看正则表达式。
• 有关其他信息，请参阅 MSDN页面。