CODEWITHSUNDEEP
iosobjective-cnsstringsubstring
blaa
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Reputation: 438

Removing last characters of NSString until it hits a separator

I've got a string that shows the stock amount using "-" as separators.

It's built up like this: localStock-wareHouseStock-supplierStock

Now I want to update the supplierStock at the end of the string, but as you can see in the code below it goes wrong when the original string returns more than a single-space value (such as 20).

Is there a way to remove all characters until the last "-" (or remove characters after the second "-")?

NSMutableString *string1 = [NSMutableString stringWithString: p1.colorStock];
                NSLog(@"string1: %@",string1);
                NSString *newString = [string1 substringToIndex:[string1 length]-2];
                NSLog(@"newString: %@",newString);
                NSString *colorStock = [NSString stringWithFormat:@"%@-%@",newString,p2.supplierStock];
                NSLog(@"colorstock: %@",colorStock);
                p1.colorStock = colorStock;

NSLog1

string1: 0-0-0
newString: 0-0
colorstock: 0-0-20

NSLog2

string1: 0-0-20
newString: 0-0-
colorstock: 0-0--20

EDIT: Got it working thanks to Srikar!

NSString *string1 = [NSString stringWithString: p1.colorStock];
                NSLog(@"string1: %@",string1);
                NSString  *finalString = [string1 stringByReplacingOccurrencesOfString:[[string1 componentsSeparatedByString:@"-"] lastObject] withString:p2.supplierStock.stringValue];
                NSLog(@"finalString: %@",finalString);
                p1.colorStock = finalString;

Upvotes: 2

Views: 2460

Answers (4)

Mark Bridges
Mark Bridges

Reputation: 8448

None of these examples show how to do this if you are unaware of how many of these separator occurrences you're going to have in the original string.

Here's what I believe the correct the correct code should be for dismantling the original string and rebuilding it until you reach the final separator, regardless of how many separators it contains.

NSString *seperator = @" ";
NSString *everythingBeforeLastSeperator;

NSArray *stringComponents = [originalString componentsSeparatedByString:seperator];

if (stringComponents.count!=0) {

    everythingBeforeLastSeperator = [stringComponents objectAtIndex:0];

    for (int a = 1 ; a < (stringComponents.count - 1) ; a++) {
        everythingBeforeLastSeperator = [NSString stringWithFormat:@"%@%@%@", everythingBeforeLastSeperator, seperator, [stringComponents objectAtIndex:a]];
    }
}

return everythingBeforeLastSeperator;

Upvotes: 0

Srikar Appalaraju
Srikar Appalaraju

Reputation: 73588

Why not use componentsSeparatedByString followed by lastObject ?

NSString *supplierStock = [[string1 componentsSeparatedByString:@"-"] lastObject];

The above works if the "stock amount" is always in sets of 3's separated by a "-". Also since you always want supplierStock, lastObject is perfect for your needs.

Of course after splitting string1 with - you get a NSArray instance and you can access the individual components using objectAtIndex:index. So if you want localStock you can get by

NSString *localStock = [[string1 componentsSeparatedByString:@"-"] objectAtIndex:0];

Upvotes: 10

Groot
Groot

Reputation: 14251

With a string that looks like

NSString *myString = @"Hello-World";

you can separate it with the componentsSeparatedByString: method of the NSString object as

NSArray *myWords = [myString componentsSeparatedByString:@"-"];

The myWords - array will then contain the two NSString objects Hello and World.

To access the strings:

NSString *theHelloString = [myWords objectAtIndex:0];
NSString *theWorldString = [myWords objectAtIndex:1];

Hope it helps!

Upvotes: 1

trojanfoe
trojanfoe

Reputation: 122391

I would suggest splitting the string into the 3 parts using [NSString componentsSeparatedByString:@"-"] and then building it back up again:

NSArray *components = [p1.colorStock componentsSeparatedByString:@"-"];
p1.colorStock = [NSString stringWithFormat:@"%@-%@-%@",
    [components objectAtIndex:0],
    [components objectAtIndex:1],
    p2.supplierStock];

Upvotes: 3

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