CODEWITHSUNDEEP
objective-ciosregexios5
Faz Ya
Faz Ya

Reputation: 1480

Use regular expression to find/replace substring in NSString

I would like to use regular expression to find every instances of a regular expression pattern I.e. &*; in my string and remove that from so the return value is the original string without any of the matches. Also would like to use the same function to match multiple spaces between words and have a single space instead. Could not find such a function.

Sample input string 

NSString *str = @"123 &1245; Ross Test  12";

Return value should be 

123 Ross Test 12

If anything matching this pattern "&* or multiple white spaces and replaces it with @"";

Upvotes: 64

Views: 57193

Answers (2)

larva
larva

Reputation: 5148

String replacing code using regex in String extension

Objective-C

@implementation NSString(RegularExpression)

- (NSString *)replacingWithPattern:(NSString *)pattern withTemplate:(NSString *)withTemplate error:(NSError **)error {
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern
                                                                           options:NSRegularExpressionCaseInsensitive
                                                                             error:error];
    return [regex stringByReplacingMatchesInString:self
                                           options:0
                                             range:NSMakeRange(0, self.length)
                                      withTemplate:withTemplate];
}

@end

resolve

NSString *string = @"123 &1245; Ross Test  12";
// remove all matches string
NSString *result = [string replacingWithPattern:@"&[\\d]+?;" withTemplate:@"" error:nil];
// result = "123  Ross Test  12"

or more

NSString *string = @"123 +   456";
// swap number
NSString *result = [string replacingWithPattern:@"([\\d]+)[ \\+]+([\\d]+)" withTemplate:@"$2 + $1" error:nil];
// result = 456 + 123

Swift2

extension String {
    func replacing(pattern: String, withTemplate: String) throws -> String {
        let regex = try NSRegularExpression(pattern: pattern, options: .CaseInsensitive)
        return regex.stringByReplacingMatchesInString(self, options: [], range: NSRange(0..<self.utf16.count), withTemplate: withTemplate)
    }
}

Swift3

extension String {
    func replacing(pattern: String, withTemplate: String) throws -> String {
        let regex = try RegularExpression(pattern: pattern, options: .caseInsensitive)
        return regex.stringByReplacingMatches(in: self, options: [], range: NSRange(0..<self.utf16.count), withTemplate: withTemplate)
    }
}

use 

var string = "1!I 2\"want 3#to 4$remove 5%all 6&digit and a char right after 7'from 8(string"
do {
    let result = try string.replacing("[\\d]+.", withTemplate: "")
} catch {
    // error
}
// result = "I want to remove all digit and a char right after from string"

Upvotes: 14

neevek
neevek

Reputation: 12128

NSString *string = @"123 &1245; Ross Test 12";
NSError *error = nil;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"&[^;]*;" options:NSRegularExpressionCaseInsensitive error:&error];
NSString *modifiedString = [regex stringByReplacingMatchesInString:string options:0 range:NSMakeRange(0, [string length]) withTemplate:@""];
NSLog(@"%@", modifiedString);

Upvotes: 163

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