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Binary Search for Javascript Arrays

Sean Murphy — Wed, 29 Apr 2009 21:41:12 +0000

If you need to search through a large array, or you search arrays frequently in your Javascript code, or if you do both, chances are a binary search will give you better performance than a linear search (read: for loop). One caveat, however, is that binary search algorithms only work on sorted arrays. Here is a binary search function I sometimes use in my code:

Array.prototype.binSearch = function(needle, case_insensitive) {
    if (!this.length) return -1;

	var high = this.length - 1;
	var low = 0;
	case_insensitive = (typeof(case_insensitive) !== 'undefined' && case_insensitive) ? true:false;
	needle = (case_insensitive) ? needle.toLowerCase():needle;

	while (low <= high) {
		mid = parseInt((low + high) / 2)
		element = (case_insensitive) ? this[mid].toLowerCase():this[mid];
		if (element > needle) {
			high = mid - 1;
		} else if (element < needle) {
			low = mid + 1;
		} else {
			return mid;
		}
	}

	return -1;
};

Recursive Find and Replace With grep and Perl

Sean Murphy — Sat, 11 Apr 2009 20:51:56 +0000

I thought it might be a nice idea to start posting useful little commands and bits of code every now and then–ones I’ve found to be particularly useful. So here’s the first one, recursive find and replace. A masterfully crafted regular expression paired with this command can save you hours of tedious work.

This will search all files recursively for SEARCH_STRING and replace all occurrences of SEARCH_STRING with REPLACE_STRING throughout each unique file found. It also creates a backup of each modified file so that FILE is backed-up as FILE~ (with a tilde).

grep -R --files-with-matches 'SEARCH_STRING' . | sort | uniq | xargs perl -pi~ -e 's/SEARCH_STRING/REPLACE_STRING/'

Taking The Pain Out Of Domain Hunting

Sean Murphy — Mon, 30 Mar 2009 17:22:45 +0000

Coming up with a suitable name for a business, product, or website is something I do on a fairly regular basis. In brainstorming a name I often make lists of words I’d like to use, like adjectives and nouns than relate the product. Then I start combining the words to create a unique name and check to see if the related domain is taken or not. The problem is that even though I may have come up with a name I really like, if the domain name is taken, it isn’t worth keeping.

These days a LOT of domains are taken, either by people using them or companies squatting them. So to make this whole process a little easier I built a website that takes most of the work out of hunting for a good domain: Trionym.The idea is fairly simple: enter up to three lists of words, choose which Top-Level Domains you’re willing to use, and search. Trionym will then create all the possible word combinations and check whois databases to see if the domains are registered. It’s relatively simple for now, but I’m considering adding more options, so if there’s a feature you’d like to see just let me know.