so I am trying to search a string for a sub string, and apparently, I must use regular expressions with the .search function, this is the code I have
var str = items[i].toLowerCase;
var str2 = document.getElementById("input").value.toLowerCase;
var index = str.search(str2);
Obhiously this doesn't work and I get an error, saying str.search is not a function, how would I go about changing these two strings into regular expressions?
thanks
Use this:
new RegExp("your regex here", "modifiers");
Take a look into: Using a string variable as regular expression
add braces to your function calls:
var str = items[i].toLowerCase();
var str2 = document.getElementById("input").value.toLowerCase();
var index = str.search(str2);
otherwise type of "str" is a function, not result of function execution
your problem is forgetting a set of brackets () -- and as such str and str2 get assigned a function rather than the result of calling that function! Simply change the code:
var str = items[i].toLowerCase();
var str2 = document.getElementById("input").value.toLowerCase();
var index = str.search(str2);
To use an expression in a RegExp constructor:
var re = new RegExp(str, 'g');
will create a regular expression to match the value of str in a string, so:
var str = 'foo';
var re = new RegExp(str, 'i');
is equivalent to the RegExp literal:
var re = /foo/i;
You can use any expression that evaluates to a valid regular expression, so to match foo at the start of a string:
var re = new RegExp('^' + str, 'i');
The only niggle is that quoted characters must be double quoted, so to match whitespace at the end of a string:
var re = new RegExp('\\s+$');
which is equivalent to:
var re = /\s+$/;
toLowerCase, is this a typo, or did you forget to actually call them? (...toLowerCase())