未定义位置只有一个空格的数字的正则表达式 [英] Regular expression for numbers with only one space in undefined positions

问题描述

我正在尝试编写一个正则表达式来验证数字，并且在未定义的位置仅用一个空格?

i am trying to write a regular expression to validate the numbers with only one space in undefined places?

最多12个字符(带一个空格)或最多11个字符(不带空格).

Maximum of 12 characters with one space or Maximum of 11 characters without spaces.

例如:"25897 569874"，"5674"，"65783987665"，"435 6523"

Ex: '25897 569874','5674','65783987665','435 6523'

我尝试使用 ^ [0-9] {0,12} $ .这不是完美的方法，因为我不知道如何放置空格及其数量.

i have tried with ^[0-9]{0,12}$.this is not perfect cause I don't know how to place the spaces and its counts.

推荐答案

您可以使用此正则表达式:

You can use this regex:

^(?:\d{1,11}|(?=\d+ \d+$)[\d ]{3,12})$

\ d {1,11} 将从1到11位数字匹配，没有空格.

\d{1,11} will match from 1 to 11 digits without space.

(?= \ d + \ d + $)[\ d] {3,12} 最多可以匹配11位数字，中间是一个空格.空格不能是前导或尾随的，因此'23'将被拒绝.

(?=\d+ \d+$)[\d ]{3,12} will match up to 11 digits with one space somewhere in the middle. The space cannot be leading or trailing, so ' 23' will be rejected.

• (?= \ d + \ d + $)是先行匹配的一个或多个数字，然后匹配一个空格，然后一个或多个数字，然后匹配字符串的末尾.它确保仅出现一个空格，并且该空格不会在前或后出现.前瞻还隐式地确认字符串中至少包含3个字符.
• [\ d] {3,12} 将确保字符串仅包含数字或空格，最多12个数字或空格.重复次数的下限可以设置为3或更低，因为前瞻已暗示了这一点.

• (?=\d+ \d+$) is a look-ahead that matched one or more digit, then a space, then one or more digit, then anchor the end of string. It guarantees only one space will appear and the space will not be leading or trailing. The look-ahead also implicitly confirms that there are at least 3 characters in the string.
• [\d ]{3,12} will guarantee the string only contains digits or space, and up to 12 of them. The lower bound of number of repetition can be set to 3 or lower, since it has been implied by the look-ahead.

这两个约束共同确保文本包含1到11个数字，并在数字之间的任意位置包含一个可选空格.

The 2 constraints together guarantees that text contains from 1 to 11 digits and an optional space at arbitrary position in between the digits.

要允许前导空格，但拒绝单个空格，空字符串和尾随空格:

To allow leading space, but reject single space, empty string and trailing spaces:

^(?:\d{1,11}|(?=\d* \d+$)[\d ]{2,12})$

同样，前瞻至少包含2个字符，因此重复次数可以设置为2个或更少.

Again, the look-ahead implies at least 2 characters, so the number of repetitions can be set to 2 or lower.

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