NSPredicate match string by words

Question

I have an array of strings as below:

["Milk","Milkshake","Milk Shake","MilkCream","Milk-Cream"]

and if I search for "milk" then results should be ["Milk","Milk Shake","Milk-Cream"] i.e. search by words.

With the predicate as

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"tagName CONTAINS[c] %@",containSearchTerm];

I am getting all the results from above array. How can I perform match using words ?

Possible duplicate of [Using Predicate in Swift](https://stackoverflow.com/questions/24176605/using-predicate-in-swift) — dahiya_boy, Mar 04 '19 at 13:32
@dahiya_boy: it's completely different. have you read my question ? — nikksindia, Mar 04 '19 at 13:34
"Milkshake" does contain "milk" so your expected result is wrong. — Joakim Danielson, Mar 04 '19 at 13:36
Have a look at https://stackoverflow.com/a/28116698/1187415 – that's in Objective-C, but shows the idea, and should be easy to translate to Swift. — Martin R, Mar 04 '19 at 13:37
Yes of course, otherwise your expected result should have been empty. As mentioned in the linked question you need to use MATCHES and regular expressions — Joakim Danielson, Mar 04 '19 at 13:39

score 6 · Accepted Answer · answered Mar 04 '19 at 13:48

You need a “regular expression search” in order to match against word boundaries, that is done with "MATCHES" in a predicate. Here is an example (essentially translated from NSPredicate with core data, search word with boundaries in string attribute to Swift):

let searchTerm = "milk"
let pattern = ".*\\b\(NSRegularExpression.escapedPattern(for: searchTerm))\\b.*"
let predicate = NSPredicate(format: "tagName MATCHES[c] %@", pattern)

This searches for all entries where the tagName contains the given search term, surrounded by a “word boundary” (the \b pattern).

NSPredicate match string by words

1 Answers1