Fuzzy Search

Using the Fuzzy Matching Utility

When you're displaying contacts, you often want to allow users to search through the list of contacts. The fuzzy matching utility makes it easy to build a fuzzy search feature into your contact selection screen.

OHFuzzyMatchingUtility *fuzzyMatchingUtility = [[OHFuzzyMatchingUtility alloc] init];

First, you need to set the allContacts property to the set of contacts you want to search through.

[dataSource.onContactsDataSourceReadySignal addObserver:self callback:^(typeof(self) self) {
    fuzzyMatchingUtility.allContacts = self.dataSource.contacts;
}];

Now we can get the results of a search query by calling the contactsMatchingQuery: method. This will return all contacts who has a match to the query string either in full name or one of its contact fields.

NSOrderedSet<OHContact *> *results = [fuzzyMatchingUtility contactsMatchingQuery:query];

Match Scoring

The fuzzy matching utility can optionally take a scoring block to perform scoring analysis on the query string. The scoring block takes as input a query string and a nominee string, and returns an NSInteger score of how "good" the match is.

For example, we could write a very simple scoring function that checks if the string is an exact match, and if so awards it a higher score.

fuzzyMatchingUtility.scoringBlock = ^NSInteger (NSString *query, NSString *nominee) {
    if ([query isEqualToString:nominee]) {
        return 5;
    }
    return 1;
};

If there is a scoring block, results will be returned in order of score (highest scores first). If the scoring block is nil, results will be returned in order of the contacts in allContacts.