Replace simultaneously multiple char in NSString - ios

Question

I am trying to replace multiple character found in a string at once not using stringByReplacingOccurrencesOfString. So if my string is: #"/BKL_UO+C-" I what to change / to _ ; - to +; + to -; _ to /.
In my code I have tried to do this by applying for each of the signs that I want to replace first the stringByReplacingOccurrencesOfString and save it as a new string and created an NSArray of chars with them. Compared the differences and save them in another array where I push all the differences from all 4 arrays. Then apply all differences to the initial string.
Initial hash string is: #"lRocUK/Qy+V2P3yDhCd74RvHjCDzlTfrGMolZZE0pcQ"
Expected result: #"lRocUK_Qy-V2P3yDhCd74RvHjCDzlTfrGMolZZE0pcQ"
NSMutableArray *originalHashArrayOfCharFromString = [NSMutableArray array];
for (int i = 0; i < [hash length]; i++) {
[originalHashArrayOfCharFromString addObject:[NSString stringWithFormat:#"%C", [hash characterAtIndex:i]]];
}
//1 change
NSString *backslashRplecedInHashString = hash;
backslashRplecedInHashString = [backslashRplecedInHashString stringByReplacingOccurrencesOfString:#"/" withString:#"_"];
NSMutableArray *hashConvertBackslashToUnderline = [NSMutableArray array];
for (int i = 0; i < [hash length]; i++) {
[hashConvertBackslashToUnderline addObject:[NSString stringWithFormat:#"%C", [backslashRplecedInHashString characterAtIndex:i]]];
}
//2 change
NSString *minusRplecedInHashString = hash;
minusRplecedInHashString = [minusRplecedInHashString stringByReplacingOccurrencesOfString:#"-" withString:#"+"];
NSMutableArray *hashConvertMinusToPlus = [NSMutableArray array];
for (int i = 0; i < [hash length]; i++) {
[hashConvertMinusToPlus addObject:[NSString stringWithFormat:#"%C", [minusRplecedInHashString characterAtIndex:i]]];
}
//3 change
NSString *underlineRplecedInHashString = hash;
underlineRplecedInHashString = [underlineRplecedInHashString stringByReplacingOccurrencesOfString:#"_" withString:#"/"];
NSMutableArray *hashConvertUnderlineToBackslash = [NSMutableArray array];
for (int i = 0; i < [hash length]; i++) {
[hashConvertUnderlineToBackslash addObject:[NSString stringWithFormat:#"%C", [underlineRplecedInHashString characterAtIndex:i]]];
}
//4 change
NSString *plusRplecedInHashString = hash;
plusRplecedInHashString = [plusRplecedInHashString stringByReplacingOccurrencesOfString:#"+" withString:#"-"];
NSMutableArray *hashConvertPlusToMinus = [NSMutableArray array];
for (int i = 0; i < [hash length]; i++) {
[hashConvertPlusToMinus addObject:[NSString stringWithFormat:#"%C", [plusRplecedInHashString characterAtIndex:i]]];
}
NSMutableArray *tempArrayForKey = [[NSMutableArray alloc] init];
NSMutableArray *tempArrayForValue = [[NSMutableArray alloc] init];
int possitionInTempArray = 0;
//Store all changes of original array in a temp array
//1 replace
for (int countPosssition = 0 ; countPosssition < [hash length]; countPosssition++) {
if ([originalHashArrayOfCharFromString objectAtIndex:countPosssition] != [hashConvertBackslashToUnderline objectAtIndex:countPosssition]) {
[tempArrayForValue addObject:[hashConvertBackslashToUnderline objectAtIndex:countPosssition]];
[tempArrayForKey addObject:[NSNumber numberWithInt:countPosssition]];
possitionInTempArray++;
}
}
//2 replace
for (int countPosssition = 0 ; countPosssition < [hash length]; countPosssition++) {
if ([originalHashArrayOfCharFromString objectAtIndex:countPosssition] != [hashConvertMinusToPlus objectAtIndex:countPosssition]) {
[tempArrayForValue addObject:[hashConvertMinusToPlus objectAtIndex:countPosssition]];
[tempArrayForKey addObject:[NSNumber numberWithInt:countPosssition]];
possitionInTempArray++;
}
}
//3 replace
for (int countPosssition = 0 ; countPosssition < [hash length]; countPosssition++) {
if ([originalHashArrayOfCharFromString objectAtIndex:countPosssition] != [hashConvertUnderlineToBackslash objectAtIndex:countPosssition]) {
[tempArrayForValue addObject:[hashConvertUnderlineToBackslash objectAtIndex:countPosssition]];
[tempArrayForKey addObject:[NSNumber numberWithInt:countPosssition]];
possitionInTempArray++;
}
}
//4 replace
for (int countPosssition = 0 ; countPosssition < [hash length]; countPosssition++) {
if ([originalHashArrayOfCharFromString objectAtIndex:countPosssition] != [hashConvertPlusToMinus objectAtIndex:countPosssition]) {
[tempArrayForValue addObject:[hashConvertPlusToMinus objectAtIndex:countPosssition]];
[tempArrayForKey addObject:[NSNumber numberWithInt:countPosssition]];
possitionInTempArray++;
}
}
NSLog(tempArrayForKey.debugDescription);
NSLog(tempArrayForValue.debugDescription);
// use the them array to submit changes
for (int count = 0; count < tempArrayForKey.count; count++) {
[originalHashArrayOfCharFromString setObject:[tempArrayForValue objectAtIndex:count] atIndexedSubscript:(int)[tempArrayForKey objectAtIndex:count]];
}
[hash setString:#""];
//Reassemble the hash string using his original array that sufferet modificvations
for (int count = 0; count<originalHashArrayOfCharFromString.count; count++) {
[hash appendString:[NSString stringWithFormat:#"%#", [originalHashArrayOfCharFromString objectAtIndex:count]]];
}
NSLog(hash);

Answer 1

What if you temporarily swapped out the occurrences to a "temp" character so you wouldn't lose data on the swaps and do something like this:
NSString * initialString = #"lRocUK/Qy+V2P3yDhCd74RvHjCDzlTfrGMolZZE0pcQ";
initialString =[initialString stringByReplacingOccurrencesOfString:#"/" withString:#"^"];
initialString =[initialString stringByReplacingOccurrencesOfString:#"-" withString:#"*"];
initialString =[initialString stringByReplacingOccurrencesOfString:#"+" withString:#"-"];
initialString =[initialString stringByReplacingOccurrencesOfString:#"*" withString:#"+"];
initialString =[initialString stringByReplacingOccurrencesOfString:#"_" withString:#"/"];
initialString =[initialString stringByReplacingOccurrencesOfString:#"^" withString:#"_"];