在Ruby中,如何匹配字符串中的所有字符,直到匹配子字符串？

Question

说我有一个字符串: Hey what's up @dude, @how's it going?

我想删除之前的所有字符@how's.

Answer 1

或者与正则表达式:

str = "Hey what's up @dude, @how's it going?"
str.gsub!(/.*?(?=@how)/im, "") #=> "@how's it going?"

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Answer 2

使用String#slice

s = "Hey what's up @dude, @how's it going?"
s.slice(s.index("@how")..-1)
# => "@how's it going?"

Answer 3

实际上有几种方法可以做到这一点.以下是我将使用的:

如果要保留原始字符串:

str = "Hey what's up @dude, @how's it going?"
str2 = str[/@how's.+/mi]
p str, str2
#=> "Hey what's up @dude, @how's it going?"
#=> "@how's it going?"

如果要改变原始字符串:

str = "Hey what's up @dude, @how's it going?"
str[/\A.+?(?=@how's)/mi] = ''
p str
#=> "@how's it going?"

...要么...

str = "Hey what's up @dude, @how's it going?"
str.sub! /\A.+?(?=@how's)/mi, ''
p str
#=> "@how's it going?"

您需要在\A字符串的开头锚定,并使用该m标志以确保您在多行之间进行匹配.

也许最简单的是改变原作:

str = "Hey what's up @dude, @how's it going?"
str.replace str[/@how's.+/mi]
p str
#=> "@how's it going?"