Rails - 从字符串中提取带有 [ 和 ] 的 substring

Question

这行得通。

"<name> <substring>"[/.*<([^>]*)/,1]
=> "substring"

但我想在[和]中提取 substring 。

输入：

string = "123 [asd]"

output ：

asd

任何人都可以帮助我吗？

Answer 1

你可以做：

"123 [asd]"[/\[(.*?)\]/, 1]

将返回

"asd"

你可以在这里测试它： https://rextester.com/YGZEA91495

Answer 2

以下是提取所需字符串的更多方法。

str = "123 [asd] 456"

#1

r = /
    (?<=\[)  # match '[' in a positive lookbehind
    [^\]]*   # match 1+ characters other than ']'
    (?=\])   # match ']' in a positive lookahead
    /x       # free-spacing regex definition mode

str[r]
  #=> "asd"

#2

r = /
    \[       # match '['
    [^\]]*   # match 1+ characters other than ']'
    \]       # match ']'
    /x       # free-spacing regex definition mode

str[r][1..-2]
  #=> "asd"

#3

r = /
    .*\[     # match 0+ characters other than a newline, then '['
    |        # or
    \].*     # match ']' then 0+ characters other than a newline
    /x       # free-spacing regex definition mode

str.gsub(r, '')
  #=> "asd"

#4

n = str.index('[')
  #=> 4
m = str.index(']', n+1)
  #=> 8
str[n+1..m-1]
  #=> "asd"

请参阅字符串#index 。