Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
210 views
in Technique[技术] by (71.8m points)

ios - Filter array by first letter of string property

I have an NSArray with objects that have a name property.

I would like filter the array by name

    NSString *alphabet = [agencyIndex objectAtIndex:indexPath.section];
    //---get all states beginning with the letter---
    NSPredicate *predicate =
    [NSPredicate predicateWithFormat:@"SELF beginswith[c] %@", alphabet];
    NSMutableArray *listSimpl = [[NSMutableArray alloc] init];
    for (int i=0; i<[[Database sharedDatabase].agents count]; i++) {
        Town *_town = [[Database sharedDatabase].agents objectAtIndex:i];
        [listSimpl addObject:_town];
    }
    NSArray *states = [listSimpl filteredArrayUsingPredicate:predicate];

But I get an error - "Can't do a substring operation with something that isn't a string (lhs = <1, Arrow> rhs = A)"

How can I do this? I would like to filter the array for the first letter in name being 'A'.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Try with following code

NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF like %@", yourName];
NSArray *filteredArr = [yourArray filteredArrayUsingPredicate:pred];

EDITED :

NSPredicate pattern should be:

NSPredicate *pred =[NSPredicate predicateWithFormat:@"name beginswith[c] %@", alphabet];

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...