I have a for loop which loops through an array and want to match a search field's text to an object in the array.
I have the following code
for (int i = 0; i < [data2 count]; i++) {
if ([data2 objectAtIndex:i] == searchField.text) {
NSLog(#"MATCH");
break;
}
}
I know in Java it can be done by e.g. if(searchField.text.equalsIgnoreCase(the object to match against))
How is this done in objective C, to match the string without case?
Also, what if I wanted to match part of the string, would that be done in Obj C char by char or is there a built in function for matching parts of Strings?
Thanks
Assuming your strings are NSStrings, you can find your answers at the NSString Class Reference
NSString supports caseInsensitiveCompare: and rangeOfString: or rangeOfString:options: if you want a case insensitive search.
The code would look like this:
if (NSOrderedSame == [searchField.text caseInsensitiveCompare:[data2 objectAtIndex:i]) {
// Do work here.
}
[[data2 objectAtIndex:i] isEqualToString: searchField.text]
You use isEqual: (to compare objects in general) or isEqualToString: (for NSStrings specifically). And you can get substrings with the substringWithRange: method.
Related
Here's my program so far. My intention is to have it so the if statement compares the letter in the string letterGuessed to a character in the string userInputPhraseString. Here's what I have. While coding in xCode, I get an "expected '['"error. I have no idea why.
NSString *letterGuessed = userInputGuessedLetter.text;
NSString *userInputPhraseString = userInputPhraseString.text;
int loopCounter = 0;
int stringLength = userInputPhraseString.length;
while (loopCounter < stringLength){
if (guessedLetter isEqualToString:[userInputPhraseString characterAtIndex:loopIndexTwo])
{
//if statement true
}
loopCounter++;
}
You are missing enclosing square brackets on this line:
if (guessedLetter isEqualToString:[userInputPhraseString characterAtIndex:loopIndexTwo])
It should be:
if ([guessedLetter isEqualToString:[userInputPhraseString characterAtIndex:loopIndexTwo]])
Edit that won’t fix your problem, though, because characterAtIndex: returns a unichar, not an NSString.
It's not clear what you are trying to do.. But I suppose that letterGuessed has one character... And that userInputPhraseString has many characters. So you want to know if letterGuessed is inside userInputPhraseString correct?
This is one solution without loops involved.. I replaced the input with fixed values for testing and tested the code.. It works.
NSString *letterGuessed = #"A"; //Change to your inputs
NSString *userInputPhraseString = #"BBBA"; //Since it has A it will be true in the test
NSCharacterSet *cset = [NSCharacterSet characterSetWithCharactersInString:letterGuessed];
NSRange range = [userInputPhraseString rangeOfCharacterFromSet:cset];
if (range.location != NSNotFound) { //Does letterGuessed is in UserInputPhraseString?
NSLog(#"YES"); //userInput Does contain A...
} else {
NSLog(#"NO");
}
In regards to your code... I fixed a couple of errors, first you are trying to get a UniChar (Integer) value for the character and want to compare it to a NSString which is an Object. Also fixed a couple of issues with syntax you had and used the right approach which is to return a range of characters. Again for doing what you want to accomplish the example above is the best approach I know, but for the sake of learning, here is your code fixed.
NSString *letterGuessed = #"A"; //Change to your inputs
NSString *userInputPhraseString = #"BBBA"; //Since it has A it will be true in the test
NSInteger loopCounter = 0; //Use NSInteger instead of int.
NSInteger stringLength = userInputPhraseString.length;
BOOL foundChar = NO; //Just for the sake of returning NOT FOUND in NSLOG
while (loopCounter < stringLength){
//Here we will get a letter for each iteration.
NSString *scannedLetter = [userInputPhraseString substringWithRange:NSMakeRange(loopCounter, 1)]; // Removed loopCounterTwo
if ([scannedLetter isEqualToString:letterGuessed])
{
NSLog(#"FOUND CHARACTER");
foundChar = YES;
}
loopCounter++;
}
if (!foundChar) NSLog(#"NOT FOUND");
NSRange holds the position, length.. So we move to a new position on every iteration and then get 1 character.
Also if this approach is what you want, I would strongly suggest a for-loop.
I'm very new to objective-c and this question may seem very simple so I am sorry if it is. I think I know how to get a user to input a string in C and comparing that to a string in an array by using strcmp. For instance (not sure if code is right as I'm not very good at c either)
char *arr[2];
arr[0] = "hello";
arr[1] = "goodbye";
char myString[10];
printf("enter greeting\n");
scanf("%s",myString);
if(strcmp(myString,arr[0]) == 0 )
{
printf("hello to you to");
}
if(strcmp(myString,arr[1]) == 0 )
{
printf("goodbye then");
}
But I'm trying to do the same thing with NSMutableArrays and NSStrings. So far it goes:
NSMutableArray *myStringArray = [[NSMutableArray alloc] init];
[myStringArray addObject:#"hello"];
[myStringArray addObject:#"goodbye"];
char greetingStr[40];
printf("enter greeting\n");
scanf("%s", greetingStr);
NSString *greeting = [NSString stringWithUTF8String:greetingStr];
//Some method to compare the strings
I was wondering what the code is the compare NSString with objects in NSMutableArrays. Sorry if it was badly explained but I am very new to programming and please keep any answers quite simple as I'm still very new to this. Thank you in advance.
"Some method to compare the strings" is:
isEqualToString:, if you're only interested in equality of strings;
compare:, if you also want to get information about their lexicographical ordering.
I am searching for an algorithm where I can compare two strings and read out the failers.
I know the normal code to compare two strings but this isn't enough.
Example:
NSString *userinput = #"xaplseiPhonr";// (Input from the user)
NSString *correct =#"apple iphone";
In the next step i would check this strings and put out the failers for this example: x,l,s, ,r = 5 failers
I tested many things, saved the two strings in an array with two for-loops and compared it but something is wrong, the hardest thing is if the word has 2 letters that are the same. Or if you have no dynamic index search then are the whole letters after the "l" or the missing space in the userinput false, and so on.
So, It would be nice if anyone has fine code for me
edit: code to compare, but this doesn't work if you missed a letter or space.
for (int i = 0; i < [originalWordLetters count]; i++)
{
NSString *originalLetter = [originalWordLetters objectAtIndex:i];
//NSLog(#"%i: %#", d, originalLetter);
BOOL letterFound = FALSE;
while (letterFound == FALSE && d < [userWordLetters count])
{
if ([originalLetter caseInsensitiveCompare:[userWordLetters objectAtIndex:d]] == NSOrderedSame)
{
//NSLog(#"letter %i correct", d+1);
letterFound = TRUE;
}
else
{
//NSLog(#"letter %i false", d+1);
failedLetters++;
}
d++;
}
}
I have a working algorithm where you can compare two strings. And put out the mistakes
I've uploaded the sample project to GitHub:
NSString compareTwoStrings: algorithm outputs the mistakes
What you want to do is compute the Damerau-Levenshtein distance between two strings. Here is an open source implementation for NSString: GitHub JanX2/NSString-DamerauLevenshtein
You can use NSScanner to do this.
I'm writing a simple shift cipher iPhone app as a pet project, and one piece of functionality I'm currently designing is a "universal" decryption of an NSString, that returns an NSArray, all of NSStrings:
- (NSArray*) decryptString: (NSString*)ciphertext{
NSMutableArray* theDecryptions = [NSMutableArray arrayWithCapacity:ALPHABET];
for (int i = 0; i < ALPHABET; ++i) {
NSString* theNewPlainText = [self decryptString:ciphertext ForShift:i];
[theDecryptions insertObject:theNewPlainText
atIndex:i];
}
return theDecryptions;
}
I'd really like to pass this NSArray into another method that attempts to spell check each individual string within the array, and builds a new array that puts the strings with the fewest typo'd words at lower indicies, so they're displayed first. I'd like to use the system's dictionary like a text field would, so I can match against words that have been trained into the phone by its user.
My current guess is to split a given string up into words, then spell check each with NSSpellChecker's -checkSpellingOfString:StartingAt: and using the number of correct words to sort the Array. Is there an existing library method or well-accepted pattern that would help return such a value for a given string?
Well, I found a solution that works using UIKit/UITextChecker. It correctly finds the user's most preferred language dictionary, but I'm not sure if it includes learned words in the actual rangeOfMisspelledWords... method. If it doesn't, calling [UITextChecker hasLearnedWord] on currentWord inside the bottom if statement should be enough to find user-taught words.
As noted in the comments, it may be prudent to call rangeOfMisspelledWords with each of the top few languages in [UITextChecker availableLanguages], to help multilingual users.
-(void) checkForDefinedWords {
NSArray* words = [message componentsSeparatedByString:#" "];
NSInteger wordsFound = 0;
UITextChecker* checker = [[UITextChecker alloc] init];
//get the first language in the checker's memory- this is the user's
//preferred language.
//TODO: May want to search with every language (or top few) in the array
NSString* preferredLang = [[UITextChecker availableLanguages] objectAtIndex:0];
//for each word in the array, determine whether it is a valid word
for(NSString* currentWord in words){
NSRange range;
range = [checker rangeOfMisspelledWordInString:currentWord
range:NSMakeRange(0, [currentWord length])
startingAt:0
wrap:NO
language:preferredLang];
//if it is valid (no errors found), increment wordsFound
if (range.location == NSNotFound) {
//NSLog(#"%# %#", #"Valid Word found:", currentWord);
wordsFound++;
}
else {
//NSLog(#"%# %#", #"Invalid Word found:", currentWord);
}
}
//After all "words" have been searched, save wordsFound to validWordCount
[self setValidWordCount:wordsFound];
[checker release];
}
Hey folks, beneath is a piece of code i used for a school assignment.
Whenever I enter a word, with an O in it (which is a capital o), it fails!
Whenever there is one or more capital O's in this program, it returns false and logs : sentence not a palindrome.
A palindrome, for the people that dont know what a palindrome is, is a word that is the same read left from right, and backwards. (e.g. lol, kayak, reviver etc)
I found this bug when trying to check the 'oldest' palindrome ever found: SATOR AREPO TENET OPERA ROTAS.
When I change all the capital o's to lowercase o's, it works, and returns true.
Let me state clearly, with this piece of code ALL sentences/words with capital O's return false. A single capital o is enough to fail this program.
-(BOOL)testForPalindrome:(NSString *)s position:(NSInteger)pos {
NSString *string = s;
NSInteger position = pos;
NSInteger stringLength = [string length];
NSString *charOne = [string substringFromIndex:position];
charOne = [charOne substringToIndex:1];
NSString *charTwo = [string substringFromIndex:(stringLength - 1 - position)];
charTwo = [charTwo substringToIndex:1];
if(position > (stringLength / 2)) {
NSString *printableString = [NSString stringWithFormat:#"De following word or sentence is a palindrome: \n\n%#", string];
NSLog(#"%# is a palindrome.", string);
[textField setStringValue:printableString];
return YES;
}
if(charOne != charTwo) {
NSLog(#"%#, %#", charOne, charTwo);
NSLog(#"%i", position);
NSLog(#"%# is not a palindrome.", string);
return NO;
}
return [self testForPalindrome:string position:position+1];
}
So, is this some weird bug in Cocoa?
Or am I missing something?
B
This of course is not a bug in Cocoa, as you probably knew deep down inside.
Your compare method is causing this 'bug in Cocoa', you're comparing the addresses of charOne and charTwo. Instead you should compare the contents of the string with the isEqualToString message.
Use:
if(![charOne isEqualToString:charTwo]) {
Instead of:
if(charOne != charTwo) {
Edit: tested it in a test project and can confirm this is the problem.
Don't use charOne != charTwo
Instead use one of the NSString Compare Methods.
if ([charOne caseInsensitiveCompare:charTwo] != NSOrderedSame)
It may also have to do with localization (but I doubt it).