Separating a single string into two Different Strings in Objective-C

Question

I am just starting off with Objective-C and iphone app dev, i'm trying to design a calculator app, the logic i have used is this : when the user clicks any button i take the title of the button by [sender titleForState:UIControlStateNormal] method and then go on appending it onto a string(NSString *result). say the user enters 123+456 , then in my string i will have "123+456", now i want two strings "123" and "456" so that i can add them by [result intValue] method.

So my question is, how do i get these two separate strings ("123" & "456")?

An example code with suitable methods would be very helpful.

To support `( )` and operator precedence you should look at parsing the input into tokens and using a grammar. — meaning-matters, Jul 09 '17 at 11:22

score 14 · Accepted Answer · answered Sep 20 '11 at 13:26

14

NSString * mystring = @"123+456";
NSArray * array = [mystring componentsSeparatedByString:@"+"];
NSString * str1 = [array objectAtIndex:0]; //123
NSString * str2 = [array objectAtIndex:1]; //456

answered Sep 20 '11 at 13:26

Youssef

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score 2 · Answer 2 · edited May 23 '17 at 12:12

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Found this at NSString tokenize in Objective-C

Found this at http://borkware.com/quickies/one?topic=NSString (useful link):

NSString *string = @"oop:ack:bork:greeble:ponies";
NSArray *chunks = [string componentsSeparatedByString: @":"];

Hope this helps!

Adam

NSString *string = @"123+456";
NSArray *chunks = [string componentsSeparatedByString: @"+"];

int res = [[chunks objectAtIndex:0] intValue]+[[chunks objectAtIndex:1] intValue];

edited May 23 '17 at 12:12

Community

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answered Sep 20 '11 at 13:29

ymutlu

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the "objectAtIndex" method was missing, but i think u expected me to figure that out :p, which ofcourse i couldn't as i'm just in the learning phase. Neway, i appreciate your taking valuable time out to think about an answer and also ofc for answering. Thanks. – wOlVeRiNe Sep 20 '11 at 16:09

score 1 · Answer 3 · answered Sep 20 '11 at 13:25

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NSArray* yourTwoStrings = [@"123+456" componentsSeparatedByString:@"+"];

answered Sep 20 '11 at 13:25

gcamp

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score 1 · Answer 4 · answered Sep 20 '11 at 13:27

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You can separate strings by using NSStrings componentsSeparatedByString:

NSString *calculation = @"1235+4362";
NSArray *results = [calculation componentsSeparatedByString:@"+"];

NSLog(@"Results: %@", results);

If you are attempting to implement a calculator you may want to familiarize yourself with Reverse Polish Notation and the Shunting-Yard Algorithm as you will find trying to create a simple calculator will be a bit more challenging than expected..

answered Sep 20 '11 at 13:27

Joe

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Thanks a lot for the postfix and algo suggestion. But the thing is that i wanna do it without using any pushing-popping mechanism i.e a stack. If my efforts don't yield success, i'll definately go with the postfix method :), thanks – wOlVeRiNe Sep 20 '11 at 16:12

Separating a single string into two Different Strings in Objective-C

4 Answers4