Shortcuts in Objective-C to concatenate NSStrings

Question

Are there any shortcuts to (stringByAppendingString:) string concatenation in Objective-C, or shortcuts for working with NSString in general?

Answer 1

My preferred method is this:

NSString *firstString = @"foo";
NSString *secondString = @"bar";
NSString *thirdString = @"baz";

NSString *joinedString = [@[firstString, secondString, thirdString] join];

You can achieve it by adding the join method to NSArray with a category:

#import "NSArray+Join.h"
@implementation NSArray (Join)
-(NSString *)join
{
    return [self componentsJoinedByString:@""];
}
@end

@[] it's the short definition for NSArray, I think this is the fastest method to concatenate strings.

If you don't want to use the category, use directly the componentsJoinedByString: method:

NSString *joinedString = [@[firstString, secondString, thirdString] componentsJoinedByString:@""];

Answer 2

For all Objective C lovers that need this in a UI-Test:

-(void) clearTextField:(XCUIElement*) textField{

    NSString* currentInput = (NSString*) textField.value;
    NSMutableString* deleteString = [NSMutableString new];

    for(int i = 0; i < currentInput.length; ++i) {
        [deleteString appendString: [NSString stringWithFormat:@"%c", 8]];
    }
    [textField typeText:deleteString];
}

Answer 3

Use stringByAppendingString: this way:

NSString *string1, *string2, *result;

string1 = @"This is ";
string2 = @"my string.";

result = [result stringByAppendingString:string1];
result = [result stringByAppendingString:string2];

OR

result = [result stringByAppendingString:@"This is "];
result = [result stringByAppendingString:@"my string."];

Answer 4

I keep returning to this post and always end up sorting through the answers to find this simple solution that works with as many variables as needed:

[NSString stringWithFormat:@"%@/%@/%@", three, two, one];

For example:

NSString *urlForHttpGet = [NSString stringWithFormat:@"http://example.com/login/username/%@/userid/%i", userName, userId];

Answer 5

listOfCatalogIDs =[@[@"id[]=",listOfCatalogIDs] componentsJoinedByString:@""];

Answer 6

When building requests for web services, I find doing something like the following is very easy and makes concatenation readable in Xcode:

NSString* postBody = {
    @"<?xml version=\"1.0\" encoding=\"utf-8\"?>"
    @"<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">"
    @" <soap:Body>"
    @"  <WebServiceMethod xmlns=\"\">"
    @"   <parameter>test</parameter>"
    @"  </WebServiceMethod>"
    @" </soap:Body>"
    @"</soap:Envelope>"
};