What's the best way to trim std::string?

Question

I\'m currently using the following code to right-trim all the std::strings in my programs:

std::string s;
s.erase(s.find_last_not_of(\" \\n\\r\\         


        

Answer 1

The above methods are great, but sometimes you want to use a combination of functions for what your routine considers to be whitespace. In this case, using functors to combine operations can get messy so I prefer a simple loop I can modify for the trim. Here is a slightly modified trim function copied from the C version here on SO. In this example, I am trimming non alphanumeric characters.

string trim(char const *str)
{
  // Trim leading non-letters
  while(!isalnum(*str)) str++;

  // Trim trailing non-letters
  end = str + strlen(str) - 1;
  while(end > str && !isalnum(*end)) end--;

  return string(str, end+1);
}