用大写字母对NSArray进行排序

Question

I have an NSArray that looks like this:

contactNamesArray = [[NSMutableArray alloc] initWithObjects:@"John Galt", @"Michael Wales", @"James Joyce", @"Shakespeare", nil];

From it, I want to make an NSArray that would have all the same values , but that would look like this:

newContactNamesArray = [[NSMutableArray alloc] initWithObjects:@"john galt", @"michael wales", @"james joyce", @"shakespeare", nil];

I want to do this because I want to make a search in that second array and I want to replace every capital letter in it with a normal letter.

How do you do something like this in Objective-C? Thanks in advance!

Answer 1

You can go through an array, and convert every element to lower case by calling

[element lowercaseString]

on it. However, this is grossly suboptimal for implementing case-insensitive search: a better approach would be keeping strings as-is, and employ caseInsensitiveCompare method for your search instead.

Answer 2

Why are you making a copy? You can sort an NSArray in a case insensitive way:

NSArray *sortedContactNamesArray = [contactNamesArray sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];

Also, bear in mind that sortedArrayUsingSelector returns an array with references to the original items, not copies of them.