I would like to count my NSArray object of my NSString. My NSArray has #"a", #"w" objects, and my string is #"abcdefgw". I would like to know how many times the #"w" object is there in my string.
You can use - (NSArray *)componentsSeparatedByString:(NSString *)separator, though this may have boundary issues. You can also use stringByReplacingOccurrencesOfString:withString: like this:
NSString *shortString = [myString stringByReplacingOccurrencesOfString:#"w" withString:#""];
return mystring.length-shortString.length;
if you are looking to count substrings you will have to search for substrings then shrink the range each time... something like.
-(NSInteger)occurrencesOfSubstring:(NSString *)substring inString:(NSString *)string
{
int occurrences =0;
NSRange searchRange = NSMakeRange(0, [string length]);
NSRange foundRange;
do {
foundRange = [string rangeOfString:substring options:NSCaseInsensitiveSearch range:searchRange];
if ((foundRange.location != NSNotFound)) {
occurrences++;
searchRange.location = foundRange.location+foundRange.length;
searchRange.length = [string length] - (foundRange.location+foundRange.length);
}
}while (foundRange.location != NSNotFound);
return occurrences;
}
Related
I'v been trying to split string to array of components by number, but have no idea how to do it. I know that each components lenght is 9 except the last one. But there is no separation between them. Maybe anyone would know how could i make this split possible?
string : E44000000R33000444V33441
And i'd like to get array with: E44000000 R33000444 V33441
in past I'v used this method, but i guess there should be a way to separate by constant number. Any ideas
NSArray *myWords = [message componentsSeparatedByString:#";"];
Please try the below code.
NSString *stringTest = #"E44000000R33000444V33441323";
NSMutableArray *arrayTest = [NSMutableArray array];
while([stringTest length] > 8) {
[arrayTest addObject:[NSString stringWithString:[stringTest substringToIndex:9]]];
stringTest = [stringTest substringFromIndex:9];
}
NSLog(#"arrayTest - %#", arrayTest);
Try this one..
NSString *mainString=#"E44000000R33000444V";
NSMutableArray *brokenString=[NSMutableArray new];
int start=0;
for (; start<mainString.length-9; start+=9) {
[brokenString addObject:[mainString substringWithRange:NSMakeRange(start, 9)]];
}
[brokenString addObject:[mainString substringFromIndex:start]];
NSLog(#"->%#",brokenString);
Output is :
->(
E44000000,
R33000444,
V
)
I investigated the NSString, and i didn't found any function like that. But you can create a category of NSString and put this function in that category and you can use as a NSString instance method.
- (NSArray *) componentSaparetedByLength:(NSUInteger) length{
NSMutableArray *array = [NSMutableArray new];
NSRange range = NSMakeRange(0, length);
NSString *subString = nil;
while (range.location + range.length <= self.length) {
subString = [self substringWithRange:range];
[array addObject:subString];
//Edit
range.location = range.length + range.location;
//Edit
range.length = length;
}
if(range.location<self.length){
subString = [self substringFromIndex:range.location];
[array addObject:subString];
}
return array;
}
You can get the substring upto the characters which you want in a loop(string length) & pass the next index for getting the next substring. After getting each substring you can add it to the array.
Used SubstringToIndex & SubstringFromIndex functions to get the substring.
Also not an requirement here, I want to propose a solution that is capable of handling characters from more sophisticated script systems, like surrogate pairs, base characters plus combining marks, Hangul jamo, and Indic consonant clusters.
#interface NSString (Split)
-(NSArray *)arrayBySplittingWithMaximumSize:(NSUInteger)size
options:(NSStringEnumerationOptions) option;
#end
#implementation NSString (Split)
-(NSArray *)arrayBySplittingWithMaximumSize:(NSUInteger)size
options:(NSStringEnumerationOptions) option
{
NSMutableArray *letterArray = [NSMutableArray array];
[self enumerateSubstringsInRange:NSMakeRange(0, [self length])
options:(option)
usingBlock:^(NSString *substring,
NSRange substringRange,
NSRange enclosingRange,
BOOL *stop) {
[letterArray addObject:substring];
}];
NSMutableArray *array = [NSMutableArray array];
[letterArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
if (idx%size == 0) {
[array addObject: [NSMutableString stringWithCapacity:size]];
}
NSMutableString *string = [array objectAtIndex:[array count]-1];
[string appendString:obj];
}];
return array;
}
#end
usage
NSArray *array = [#"E44000000R33000444V33441" arraysBySplittingWithMaximumSize:9
options:NSStringEnumerationByComposedCharacterSequences];
results in:
(
E44000000,
R33000444,
V33441
)
I've got an algorithm to find anagrams within a group of eight-letter words. Effectively it's alphabetizing the letters in the longer word, doing the same with the shorter words one by one, and seeing if they exist in the longer word, like so:
tower = eortw
two = otw
rot = ort
The issue here is that if I look for ort in eortw (or rot in tower), it'll find it, no problem. Rot is found inside tower. However, otw is not inside eortw (or two in tower), because of the R in the middle. Ergo, it doesn't think two is found in tower.
Is there a better way I can do this? I'm trying to do it in Objective-C, and both the eight-letter words and regular words are stored in NSDictionaries (with their normal and alphabetized forms).
I've looked at various other posts re. anagrams on StackOverflow, but none seem to address this particular issue.
Here's what I have so far:
- (BOOL) doesEightLetterWord: (NSString* )haystack containWord: (NSString *)needle {
for (int i = 0; i < [needle length] + 1; i++) {
if (!needle) {
NSLog(#"DONE!");
}
NSString *currentCharacter = [needle substringWithRange:NSMakeRange(i, 1)];
NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString: currentCharacter];
NSLog(#"Current character is %#", currentCharacter);
if ([haystack rangeOfCharacterFromSet:set].location == NSNotFound) {
NSLog(#"The letter %# isn't found in the word %#", currentCharacter, haystack);
return FALSE;
} else {
NSLog(#"The letter %# is found in the word %#", currentCharacter, haystack);
int currentLocation = [haystack rangeOfCharacterFromSet: set].location;
currentLocation++;
NSString *newHaystack = [haystack substringFromIndex: currentLocation];
NSString *newNeedle = [needle substringFromIndex: i + 1];
NSLog(#"newHaystack is %#", newHaystack);
NSLog(#"newNeedle is %#", newNeedle);
}
}
}
If you use only part of the letters it isn't a true anagram.
A good algorithm in your case would be to take the sorted strings and compare them letter by letter, skipping mis-matches in the longer word. If you reach the end of the shorter word then you have a match:
char *p1 = shorter_word;
char *p2 = longer_word;
int match = TRUE;
for (;*p1; p1++) {
while (*p2 && (*p2 != *p1)) {
p2++;
}
if (!*p2) {
/* Letters of shorter word are not contained in longer word */
match = FALSE;
}
}
This is one that approach I might take for finding out if one ordered word contained all of the letters of another ordered word. Note that it won't find true anagrams (That simply requires the two ordered strings to be the same) but this does what I think you're asking for:
+(BOOL) does: (NSString* )longWord contain: (NSString *)shortWord {
NSString *haystack = [longWord copy];
NSString *needle = [shortWord copy];
while([haystack length] > 0 && [needle length] > 0) {
NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString: [needle substringToIndex:1]];
if ([haystack rangeOfCharacterFromSet:set].location == NSNotFound) {
return NO;
}
haystack = [haystack substringFromIndex: [haystack rangeOfCharacterFromSet: set].location+1];
needle = [needle substringFromIndex: 1];
}
return YES;
}
The simplest (but not most efficient) way might be to use NSCountedSet. We can do this because for counted sets, [a isSubsetOfSet:b] return YES if and only if [a countForObject:object] <= [b countForObject:object] for every object in a.
Let's add a category to NSString to do it:
#interface NSString (lukech_superset)
- (BOOL)lukech_isSupersetOfString:(NSString *)needle;
#end
#implementation NSString (lukech_superset)
- (NSCountedSet *)lukech_countedSetOfCharacters {
NSCountedSet *set = [NSCountedSet set];
[self enumerateSubstringsInRange:NSMakeRange(0, self.length) options:NSStringEnumerationByComposedCharacterSequences usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
[set addObject:substring];
}];
return set;
}
- (BOOL)lukech_isSupersetOfString:(NSString *)needle {
return [[needle lukech_countedSetOfCharacters] isSubsetOfSet:[self lukech_countedSetOfCharacters]];
}
#end
What is the easiest and best way in Objective-C to combine a list (NSArray) of NSStrings into a single NSString separated by commas, with the grammatically correct terminal conjunction ", and " before the final item of the list?
NSArray *anArray = [NSArray arrayWithObjects:#"milk", #"butter", #"eggs", #"spam", nil];
From this array, I want the NSString #"milk, butter, eggs, and spam".
More generally, if the list is more than two items long, I want ", " between every item except the last and second-to-last (which should have ", and "). If the list is two items long, I want just the ' and ' with no comma. If the list is one item long, I want the single string from the array.
I like something as simple as:
NSString *newString = [anArray componentsJoinedByString:#", "];
But this of course omits the 'and' conjunction.
Is there a simpler and/or faster Objective-C way than the following:
- (NSString *)grammaticallyCorrectStringFromArrayOfStrings:(NSArray *)anArray {
if (anArray == nil) return nil;
int arrayCount = [anArray count];
if (arrayCount == 0) return #"";
if (arrayCount == 1) return [anArray objectAtIndex:0];
if (arrayCount == 2) return [anArray componentsJoinedByString:#" and "];
// arrayCount > 2
NSString *newString = #"";
for (NSString *thisString in anArray) {
if (thisString != [anArray objectAtIndex:0] && thisString != [anArray lastObject]) {
newString = [newString stringByAppendingString:#", "];
}
else if (thisString == [anArray lastObject]) {
newString = [newString stringByAppendingString:#", and "];
}
newString = [newString stringByAppendingString:thisString];
}
return newString;
}
For the loop, I'd probably do something like
NSMutableString *newString = [NSMutableString string];
NSUInteger lastIndex = arrayCount - 1;
[anArray enumerateObjectsUsingBlock:^(NSString *thisString, NSUInteger idx, BOOL *stop) {
if (idx != 0)
[newString appendString:#","];
if (idx == lastIndex)
[newString appendString:#" and "];
[newString appendString:thisString];
}];
Though I guess that's not really less lines.
I am trying to replace all characters except last 4 in a String with *'s.
In objective-c there is a method in NSString class replaceStringWithCharactersInRange: withString: where I would give it range (0,[string length]-4) ) with string #"*". This is what it does: 123456789ABCD is modified to *ABCD while I am looking to make ********ABCD.
I understand that it replaced range I specified with string object. How to accomplish this ?
NSError *error;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"\\d" options:NSRegularExpressionCaseInsensitive error:&error];
NSString *newString = [regex stringByReplacingMatchesInString:string options:0 range:NSMakeRange(0, [string length]) withTemplate:#"*"];
This looks like a simple problem... get the first part string and return it with the last four characters appended to it.
Here is a function that returns the needed string :
-(NSString *)neededStringWithString:(NSString *)aString {
// if the string has less than or 4 characters, return nil
if([aString length] <= 4) {
return nil;
}
NSUInteger countOfCharToReplace = [aString length] - 4;
NSString *firstPart = #"*";
while(--countOfCharToReplace) {
firstPart = [firstPart stringByAppendingString:#"*"];
}
// range for the last four
NSRange lastFourRange = NSMakeRange([aString length] - 4, 4);
// return the combined string
return [firstPart stringByAppendingString:
[aString substringWithRange:lastFourRange]];
}
The most unintuitive part in Cocoa is creating the repeating stars without some kind of awkward looping. stringByPaddingToLength:withString:startingAtIndex: allows you to create a repeating string of any length you like, so once you have that, here's a simple solution:
NSInteger starUpTo = [string length] - 4;
if (starUpTo > 0) {
NSString *stars = [#"" stringByPaddingToLength:starUpTo withString:#"*" startingAtIndex:0];
return [string stringByReplacingCharactersInRange:NSMakeRange(0, starUpTo) withString:stars];
} else {
return string;
}
I'm not sure why the accepted answer was accepted, since it only works if everything but last 4 is a digit. Here's a simple way:
NSMutableString * str1 = [[NSMutableString alloc]initWithString:#"1234567890ABCD"];
NSRange r = NSMakeRange(0, [str1 length] - 4);
[str1 replaceCharactersInRange:r withString:[[NSString string] stringByPaddingToLength:r.length withString:#"*" startingAtIndex:0]];
NSLog(#"%#",str1);
You could use [theString substringToIndex:[theString length]-4] to get the first part of the string and then combine [theString length]-4 *'s with the second part. Perhaps their is an easier way to do this..
NSMutableString * str1 = [[NSMutableString alloc]initWithString:#"1234567890ABCD"];
[str1 replaceCharactersInRange:NSMakeRange(0, [str1 length] - 4) withString:#"*"];
NSLog(#"%#",str1);
it works
The regexp didn't work on iOS7, but perhaps this helps:
- (NSString *)encryptString:(NSString *)pass {
NSMutableString *secret = [NSMutableString new];
for (int i=0; i<[pass length]; i++) {
[secret appendString:#"*"];
}
return secret;
}
In your case you should stop replacing the last 4 characters. Bit crude, but gets the job done
I have following array and search string.
NSArray *values =[NSArray arrayWithObjects:#"abc",#"xyz",#"cba",#"yzx",nil];
NSString *search = #"startcba";
I want to search string's end part within an array elements. My expected search result will be #"cba". Please let me know how to find the desire value in array for giving search.
Thanks,
You can use NSPredicate to get the elements that satisfy your requirement.
NSPredicate * predicate = [NSPredicate predicateWithFormat:#" %# ENDSWITH SELF ", search];
NSArray * searchResults = [values filteredArrayUsingPredicate:predicate];
The NSPredicates way is great.
Here is an approach with rangeOfString:
NSArray *values =[NSArray arrayWithObjects:#"abc",#"xyz",#"cba",#"yzx",nil];
NSString *search = #"startcba";
NSUInteger searchLength = [search length];
NSString *result = nil;
for (NSString *val in values)
{
NSUInteger valLength = [val length];
NSRange expectedRange = NSMakeRange(searchLength - valLength, valLength);
NSRange rng = [search rangeOfString:val];
if ( rng.location == expectedRange.location && rng.length == expectedRange.length )
{
result = val;
break;
}
}