Question

I have this string (2.5+1)*5

I want to make a NSMutableArray containing each of the elements:
[(, 2.5, +, 1, ), *, 5]

This is the code I wrote:

+ (NSMutableArray*) convertToList: (NSString *) exp {
    NSRegularExpression * reg = [NSRegularExpression regularExpressionWithPattern: @"(\\d+\\.\\d+)|(\\d+)|([+-/*///^])|([/(/)])" options:0 error:nil];
    NSArray *matches = [ reg matchesInString: exp
                                 options: 0
                                   range:NSMakeRange(0, [exp length])];
    return [matches mutableCopy];
}

int main (int argc, char *argv[]) {
    NSString * exp = @"(2+5)";
    NSMutableArray * array = [ExpressionTexting convertToList:exp];
    NSLog(@"%@", array);
}

I get this output:

(
"<NSExtendedRegularExpressionCheckingResult: 0x10010d2e0>{0, 1}{<NSRegularExpression: 0x10010abb0> (\\d+\\.\\d+)|(\\d+)|([+-/*///^])|([/(/)]) 0x0}",
"<NSExtendedRegularExpressionCheckingResult: 0x10010d3f0>{1, 1}{<NSRegularExpression: 0x10010abb0> (\\d+\\.\\d+)|(\\d+)|([+-/*///^])|([/(/)]) 0x0}",
"<NSExtendedRegularExpressionCheckingResult: 0x10010d470>{2, 1}{<NSRegularExpression: 0x10010abb0> (\\d+\\.\\d+)|(\\d+)|([+-/*///^])|([/(/)]) 0x0}",
"<NSExtendedRegularExpressionCheckingResult: 0x10010d4f0>{3, 1}{<NSRegularExpression: 0x10010abb0> (\\d+\\.\\d+)|(\\d+)|([+-/*///^])|([/(/)]) 0x0}",
"<NSExtendedRegularExpressionCheckingResult: 0x10010d570>{4, 1}{<NSRegularExpression: 0x10010abb0> (\\d+\\.\\d+)|(\\d+)|([+-/*///^])|([/(/)]) 0x0}"
)

In Java I got the answer:

public static ArrayList<String> convertToList(String exp){
    String regex = "(\\d+\\.\\d+)|(\\d+)|([+-/*///^])|([/(/)])";
    Matcher m3 = Pattern.compile(regex).matcher(exp);
    ArrayList<String> list = new ArrayList<String>(exp.length());
    while (m3.find()) {
        list.add(m3.group());
    }
    return list;
}

Which works, but I can’t translate it in Objective-c

Answer 1

I found the solution, the error was due to the fact that I didn’t really know how to handle the result, the NSArray returned is made of NSTextCheckingResult, which I have to use to extract the numbers and the operators.

+ (NSMutableArray*) convertToList: (NSString *) exp {
NSRegularExpression * reg = [NSRegularExpression regularExpressionWithPattern: @"(\\d+\\.\\d+)|(\\d+)|([+-/*///^])|([/(/)])" options:0 error:nil];
NSArray *matches = [ reg matchesInString: exp
                                 options: 0
                                   range:NSMakeRange(0, [exp length])];

NSMutableArray *mArray = [[NSMutableArray alloc] init];
for (NSTextCheckingResult *match in matches) {
    NSString* matchText = [exp substringWithRange:[match range]];
    [mArray addObject:matchText];
    //NSLog(@"%@", matchText);
}

return mArray;
}