假设我有两个字符串:
- “这个测试有一个”
- “这有一个测试”
如何匹配字符串末尾的“测试”并且只得到第二个而不是第一个字符串。我正在使用include?
,但它会匹配所有出现,而不仅仅是子字符串出现在字符串末尾的那些。
您可以非常简单地使用end_with?
,例如
"Test something Test".end_with? 'Test'
或者,您可以使用匹配字符串结尾的正则表达式:
/Test$/ === "Test something Test"
"This-Test has a ".end_with?("Test") # => false
"This has a-Test".end_with?("Test") # => true
哦,可能性很多...
假设我们有两个字符串,a = "This-Test has a"
并且b = "This has a-Test
.
因为你想匹配任何完全以 结尾的字符串"Test"
,所以一个好的正则表达式应该是/Test$/
“大写 T,后跟e
,然后s
,然后t
,然后是行尾 ( $
)”。
Ruby 具有=~
对字符串(或类似字符串的对象)执行 RegEx 匹配的运算符:
a =~ /Test$/ # => nil (because the string does not match)
b =~ /Test$/ # => 11 (as in one match, starting at character 11)
你也可以使用String#match
:
a.match(/Test$/) # => nil (because the string does not match)
b.match(/Test$/) # => a MatchData object (indicating at least one hit)
或者你可以使用String#scan
:
a.scan(/Test$/) # => [] (because there are no matches)
b.scan(/Test$/) # => ['Test'] (which is the matching part of the string)
或者你可以只使用===
:
/Test$/ === a # => false (because there are no matches)
/Test$/ === b # => true (because there was a match)
或者您可以使用String#end_with?
:
a.end_with?('Test') # => false
b.end_with?('Test') # => true
...或其他几种方法之一。任你选。
您可以使用正则表达式/Test$/
进行测试:
"This-Test has a " =~ /Test$/
#=> nil
"This has a-Test" =~ /Test$/
#=> 11
您可以使用范围:
"Your string"[-4..-1] == "Test"
您可以使用正则表达式:
"Your string " =~ /Test$/
String[]
让它变得漂亮、简单和干净:
"This-Test has a "[/Test$/] # => nil
"This has a-Test"[/Test$/] # => "Test"
如果您需要不区分大小写:
"This-Test has a "[/test$/i] # => nil
"This has a-Test"[/test$/i] # => "Test"
如果你想要真/假:
str = "This-Test has a "
!!str[/Test$/] # => false
str = "This has a-Test"
!!str[/Test$/] # => true