Objective C Tutorial - Objective C String Operations
Append sub string
#import <Foundation/Foundation.h>
int main ()
{
NSMutableString *largeString;
largeString = [NSMutableString stringWithString: @"That is a string"];
NSLog (@"Original string = %@", largeString);
[largeString appendString: @" and this is a string too."];
NSLog (@"New string = %@", largeString);
return 0;
}
The code above generates the following result.
Check prefix and suffixes
#import <Foundation/Foundation.h>
int main ()
{
NSString *myName = @"John Doe";
NSString *hisName = @"John Doe";
if ([myName isEqualToString: hisName])
{
NSLog (@"The two strings are equal using isEqualToString.");
}
BOOL flag;
flag = [myName hasPrefix: @"John"];
if (flag)
{
NSLog (@"The hasPrefix method returned YES.");
}
return 0;
}
The code above generates the following result.
Convert string to number
#import <Foundation/Foundation.h>
int main ()
{
NSString *integerString = @"47";
NSString *floatString = @"52.7016";
int myInteger;
float myFloat;
myInteger = [integerString intValue];
myFloat = [floatString floatValue];
NSLog (@"Integer value = %i", myInteger);
NSLog (@"Float value = %f", myFloat);
NSLog (@"**********");
myInteger = [floatString integerValue];
myFloat = [integerString floatValue];
NSLog (@"Integer value = %i", myInteger);
NSLog (@"Float value = %f", myFloat);
return 0;
}
The code above generates the following result.
Convert to uppercase and lowercase
#import <Foundation/Foundation.h>
int main ()
{
NSString *testString = @"Greetings from another planet!";
NSString *targetString;
targetString = [testString uppercaseString];
NSLog (@"All uppercase = %@", targetString);
NSLog (@"**********");
targetString = [testString lowercaseString];
NSLog (@"All lowercase = %@", targetString);
NSLog (@"**********");
targetString = [testString capitalizedString];
NSLog (@"All capitalized strings = %@", targetString);
NSLog (@"**********");
NSLog (@"Original string = %@", testString);
return 0;
}
The code above generates the following result.
Delete part of a string
#import <Foundation/Foundation.h>
int main ()
{
NSMutableString *largeString;
largeString = [NSMutableString stringWithString: @"That is a string"];
NSLog (@"Original string = %@", largeString);
[largeString deleteCharactersInRange: [largeString rangeOfString: @"is a "]];
NSLog (@"New string = %@", largeString);
return 0;
}
The code above generates the following result.
Extracting a Substring to the End of a String
#import <Foundation/Foundation.h>
int main ()
{
NSMutableString *largeString;
largeString = [NSMutableString stringWithString: @"That is a string"];
NSLog (@"Original string = %@", largeString);
NSString *newString;
newString = [largeString substringFromIndex: 5];
NSLog (@"New string = %@", newString);
return 0;
}
The code above generates the following result.
Extracting a Substring with Location and Length
#import <Foundation/Foundation.h>
int main ()
{
NSMutableString *largeString;
largeString = [NSMutableString stringWithString: @"That is a string"];
NSLog (@"Original string = %@", largeString);
NSString *newString;
newString = [largeString substringWithRange: NSMakeRange(5, 4)];
NSLog (@"New string = %@", newString);
return 0;
}
The code above generates the following result.
Get the length of a string
#import <Foundation/Foundation.h>
int main ()
{
NSString *myString = @"Hello, world!";
int counter;
counter = [myString length];
NSLog (@"String length = %i", counter);
return 0;
}
The code above generates the following result.
Insert a string
#import <Foundation/Foundation.h>
int main ()
{
NSMutableString *largeString;
largeString = [NSMutableString stringWithString: @"That is a string"];
NSLog (@"Original string = %@", largeString);
[largeString insertString: @"was and still " atIndex: 5];
NSLog (@"New string = %@", largeString);
return 0;
}
The code above generates the following result.
Searching and Replacing Strings
#import <Foundation/Foundation.h>
int main ()
{
NSMutableString *largeString;
largeString = [NSMutableString stringWithString: @"That is a string"];
NSLog (@"Original string = %@", largeString);
[largeString replaceCharactersInRange: NSMakeRange(5,2) withString: @"was not"];
NSLog (@"New string = %@", largeString);
return 0;
}
The code above generates the following result.
Searching and Replacing Part of a String
#import <Foundation/Foundation.h>
int main ()
{
NSMutableString *largeString;
largeString = [NSMutableString stringWithString: @"That is a string"];
NSLog (@"Original string = %@", largeString);
[largeString replaceCharactersInRange: [largeString rangeOfString: @"is"] withString: @"was not"];
NSLog (@"New string = %@", largeString);
return 0;
}
The code above generates the following result.
Searching for a Substring
#import <Foundation/Foundation.h>
int main ()
{
NSRange myRange;
NSString *bigString = @"Learning to program can be fun!";
myRange = [bigString rangeOfString: @"can be"];
if (myRange.location == NSNotFound)
{
NSLog (@"Substring is not in %@", bigString);
}
else
{
NSLog (@"Substring found at location = %i", myRange.location);
NSLog (@"Substring length = %i", myRange.length);
}
return 0;
}
The code above generates the following result.
Compare two Strings
#import <Foundation/Foundation.h> int main (int argc, const char * argv[]) { NSString *myString1 = @"A"; NSString *myString2 = @"B"; NSString *myString3 = @"A"; BOOL isEqual = [myString1 isEqualToString:myString2]; if(isEqual) NSLog(@"%@ is equal to %@", myString1, myString2); else NSLog(@"%@ is not equal to %@", myString1, myString2); if([myString1 isEqualToString:myString2]) NSLog(@"%@ is equal to %@", myString1, myString2); else NSLog(@"%@ is not equal to %@", myString1, myString2); if([myString1 isEqualToString:myString3]) NSLog(@"%@ is equal to %@", myString1, myString3); else NSLog(@"%@ is not equal to %@", myString1, myString3); NSString *name = @"Mr. John Smith, MD"; BOOL hasMrPrefix = [name hasPrefix:@"Mr"]; if(hasMrPrefix) NSLog(@"%@ has the Mr prefix", name); else NSLog(@"%@ doesn't have the Mr prefix", name); BOOL hasMDSuffix = [name hasSuffix:@"MD"]; if(hasMDSuffix) NSLog(@"%@ has the MD suffix", name); else NSLog(@"%@ doesn't have the MD suffix", name); NSString *alphabet = @"ABCDEFGHIJKLMONPQRSTUVWXYZ"; NSRange range = NSMakeRange(2, 3); BOOL lettersInRange = [[alphabet substringWithRange:range] isEqualToString:@"CDE"]; if(lettersInRange) NSLog(@"The letters CDE are in alphabet starting at position 2"); else NSLog(@"The letters CDE aren't in alphabet starting at position 2"); return 0; }
The code above generates the following result.
Get a Range of String
#import <Foundation/Foundation.h> int main (int argc, const char * argv[]) { NSMutableString *myString = [[NSMutableString alloc] initWithCapacity:26]; [myString setString:@"ABCDEFGHIJKLMONPQRSTUVWXYZ"]; NSLog(@"%@", myString); [myString appendString:@", 0123456789"]; NSLog(@"%@", myString); [myString insertString:@"abcdefg, " atIndex:0]; NSLog(@"%@", myString); NSRange range = NSMakeRange(9, 3); [myString deleteCharactersInRange:range]; NSLog(@"%@", myString); NSRange rangeOfString = [myString rangeOfString:myString]; [myString replaceOccurrencesOfString:@", " withString:@"|" options:NSCaseInsensitiveSearch range:rangeOfString]; NSLog(@"%@", myString); NSRange rangeToReplace = NSMakeRange(0, 4); [myString replaceCharactersInRange:rangeToReplace withString:@"MORE"]; NSLog(@"%@", myString); return 0; }
The code above generates the following result.
