Use regular expression to find/replace substring in NSString - objective-c

Question

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 #"";

Answer 1

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);

Answer 2

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"