ruby on rails，如果它是*符号，则替换最后一个字符

Question

I have a string and I need to check whether the last character of that string is *, and if it is, I need to remove it.

if stringvariable.include? "*"
 newstring = stringvariable.gsub(/[*]/, '')
end

The above does not search if the '*' symbol is the LAST character of the string.

How do i check if the last character is '*'?

Thanks for any suggestion

Answer 1

Use the $ anchor to only match the end of line:

"sample*".gsub(/\*$/, '')

If there's the possibility of there being more than one * on the end of the string (and you want to replace them all) use:

"sample**".gsub(/\*+$/, '')

Answer 2

You can also use chomp ( see it on API Dock ), which removes the trailing record separator character(s) by default, but can also take an argument, and then it will remove the end of the string only if it matches the specified character(s).

"hello".chomp            #=> "hello"
"hello\n".chomp          #=> "hello"
"hello\r\n".chomp        #=> "hello"
"hello\n\r".chomp        #=> "hello\n"
"hello\r".chomp          #=> "hello"
"hello \n there".chomp   #=> "hello \n there"
"hello".chomp("llo")     #=> "he"
"hello*".chomp("*")      #=> "hello"

Answer 3

String has an end_with? method

stringvariable.chop! if stringvariable.end_with? '*'

Answer 4

You can either use a regex or just splice the string:

if string_variable[-1] == '*'
  new_string = string_variable.gsub(/[\*]/, '') # note the escaped *
end

That only works in Ruby 1.9.x...

Otherwise you'll need to use a regex:

if string_variable =~ /\*$/
  new_string = string_variable.gsub(/[\*]/, '') # note the escaped *
end

But you don't even need the if :

new_string = string_variable.gsub(/\*$/, '')

Answer 5

You can do the following which will remove the offending character, if present. Otherwise it will do nothing:

your_string.sub(/\*$/, '')

If you want to remove more than one occurrence of the character, you can do:

your_string.sub(/\*+$/, '')

Of course, if you want to modify the string in-place, use sub! instead of sub

Cheers, Aaron