Question

我有一个这样的字符串：

var str = "this is test
           1. this is test
           2. this is test
              3. this is test
           this is test
           1. this test
                   2. this is test";

我想要2。

另一个例子：

var str = "this is test
           1. this is test
           2. this is test
              3. this is test
           this is test
           1. this test
                   2. this is test
           this is test";

我想要2。

另一个例子：

var str = "this is test
           1. this is test
           2. this is test
              3. this is test
           this is test
           1. this test
                   2. this is test

           this is test";

我想要null，因为两个连续的\n打破了这个序列。

如您所见，我想要列表样式的最后一个数字。像这样：

{spaces in here doesn't matter}{any digit}{dot}{every thing in here til end of line}

我该怎么做？

Answer 1

尝试这种模式

^[\s\S]*(?:^|\r?\n)\s+(\d+)(?![\s\S]*(\r?\n){2})

Demo

使用数字后的强制点

^[\s\S]*(?:^|\r?\n)\s+(\d+)\.(?![\s\S]*(\r?\n){2})

说明：

^[\s\S]*                    # from the beginning "^" consume everything
(?:^|\r?\n)                 # if not first line then followed by a newline
\s*                         # followed by white spaces
(\d+)                       # capturing group to get your number
(?!                         # a negative look-ahead
    [\s\S]*(\r?\n){2}       # anything followed by {2} new lines
)                           # end of negative look-ahead

Answer 2

这应该就像运行

一样简单

(string.match(/[0-9]+/gm) || []).pop()

这将搜索多行字符串中的数字并取最后一个字符串。如果没有找到数字，它将回退到一个空数组，该数组将返回undefined pop()。听起来就像你需要的那样

如何选择字符串中的最后一个数字？

2 个答案: