普通的前pression匹配的美元金额 [英] Regular expression to match dollar amounts

问题描述

有谁以下模式提供我经常EX pression？

$ 1234

$ 31234.3

$ 1234.56

$ 123456.78

$ 99

我的要求是十进制数字前应不超过6小数点后不应超过2位数。请帮帮我。在此先感谢..

解决方案

  ^ \\ $（？=。* \\ D）\\ D {0,6}（\\。\\ D { 1,2}）$？
 

（？=。* \\ D）确保有字符串中的至少一个数字。如果没有，正则表达式 ^ \\ $ \\ D {0,6}（\\。\\ D {1,2}）？$ 将匹配字符串 $ 。

顺便说一句，超前不一定是这个长;即使是一个简单的（？=）会做，因为正则表达式可以确保后续字符确实有效。因此，它可以被简化为

  ^ \\ $（？=）\\ D {0,6}（\\。\\ D {1,2}）$？
 

Could anybody provide me the regular expression for the following patterns?

$1234

$31234.3

$1234.56

$123456.78

$.99

My requirement is the digits before decimal should not exceed 6 and after the decimal point it should not exceed 2 digits. Please help me. Thanks in advance..

解决方案

^\$(?=.*\d)\d{0,6}(\.\d{1,2})?$

(?=.*\d) makes sure that there is at least one digit in the string. Without that, the regex ^\$\d{0,6}(\.\d{1,2})?$ would match the string $.

Btw, the lookahead need not be this long; even a simple (?=.) would do, as the regex makes sure that the subsequent characters are indeed valid. Thus, it can be simplified to

^\$(?=.)\d{0,6}(\.\d{1,2})?$

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