使用charAt（）查找空格，换行符和制表符

Question

I'm trying to check if there is a space, a newline or a tab at the current character location. Spaces work but tabs and newlines dont. Go figure, I'm using escapes for those, and just a regular space for a space... What's the correct way to find these at a location?

if(String.valueOf(txt.charAt(strt)).equals(" ") || 
                    txt.charAt(strt) == '\r' ||
                    txt.charAt(strt) == '\n' || 
                    txt.charAt(strt) == '\t') {
    //do stuff
                    }

Answer 1

This works for me:

  char c = txt.charAt(strt);
  if (c == ' ' || c == '\t' || c == '\n' || c == '\r')
    System.out.println("Found one at " + strt);

Yours works too, although it's a bit harder to follow. Why it doesn't work for you I don't know - maybe the string is badly formed? Are you sure you actually have tabs and stuff in it?

Answer 2

It should work just fine, check your input string. Also, the space can be checked by comparing a blank space character. Creating a new String object just for comparison is costly.

Answer 3

This regex [\\s] will do the work. It matches the whitespace, Equivalent to [\\t\\n\\r\\f].

Answer 4

Looking at the docs for Editable in android, it returns a char . Therefore ...

if (txt.charAt(strt) == ' ' || 
    txt.charAt(strt) == '\r' ||
    txt.charAt(strt) == '\n' || 
    txt.charAt(strt) == '\t') 
{
    //do stuff
}

Will produce the expected result.