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I have some string value which constructed from a few characters , and i want to check if they exist in another NSString, without case sensitive, and spaces .
Example code :
NSString *me = #"toBe" ;
NSString *target=#"abcdetoBe" ;
//than check if me is in target.
Here i will get true because me exist in target .
How can i check for such condition ?
I have read How do I check if a string contains another string in Objective-C? but its case sensitive and i need to find with no case sensitive..
Use the option NSCaseInsensitiveSearch with rangeOfString:options:
NSString *me = #"toBe" ;
NSString *target = #"abcdetobe" ;
NSRange range = [target rangeOfString: me options: NSCaseInsensitiveSearch];
NSLog(#"found: %#", (range.location != NSNotFound) ? #"Yes" : #"No");
if (range.location != NSNotFound) {
// your code
}
NSLog output:
found: Yes
Note: I changed the target to demonstrate that case insensitive search works.
The options can be "or'ed" together and include:
NSCaseInsensitiveSearch
NSLiteralSearch
NSBackwardsSearch
NSAnchoredSearch
NSNumericSearch
NSDiacriticInsensitiveSearch
NSWidthInsensitiveSearch
NSForcedOrderingSearch
NSRegularExpressionSearch
-(BOOL)substring:(NSString *)substr existsInString:(NSString *)str {
if(!([str rangeOfString:substr options:NSCaseInsensitiveSearch].length==0)) {
return YES;
}
return NO;
}
usage:
NSString *me = #"toBe";
NSString *target=#"abcdetoBe";
if([self substring:me existsInString:target]) {
NSLog(#"It exists!");
}
else {
NSLog(#"It does not exist!");
}
As with the release of iOS8, Apple added a new method to NSStringcalled localizedCaseInsensitiveContainsString. This will exactly do what you want:
Swift:
let string: NSString = "ToSearchFor"
let substring: NSString = "earch"
string.localizedCaseInsensitiveContainsString(substring) // true
Objective-C:
NSString *string = #"ToSearchFor";
NSString *substring = #"earch";
[string localizedCaseInsensitiveContainsString:substring]; //true
I'm trying to cut the length of an NSString without splitting the last word with this method:
// cut a string by words
- (NSString* )stringCutByWords:(NSString *)string toLength:(int)length;
{
// search backwards in the string for the beginning of the last word
while ([string characterAtIndex:length] != ' ' && length > 0) {
length--;
}
// if the last word was the first word of the string search for the end of the word
if (length <= 0){
while ([string characterAtIndex:length] != ' ' && length > string.length-1) {
length++;
}
}
// define the range you're interested in
NSRange stringRange = {0, length};
// adjust the range to include dependent chars
stringRange = [string rangeOfComposedCharacterSequencesForRange:stringRange];
// Now you can create the short string
string = [string substringWithRange:stringRange];
return [NSString stringWithFormat:#"%#...",string];
}
now my question is:
Is there a build-in way in objective-c or cocoa-touch which i did not see or else is there a "nicer" way to do this because iam not very happy with this solution.
greetings and thanks for help
C4rmel
My proposal for a Category method
#interface NSString (Cut)
-(NSString *)stringByCuttingExceptLastWordWithLength:(NSUInteger)length;
#end
#implementation NSString (Cut)
-(NSString *)stringByCuttingExceptLastWordWithLength:(NSUInteger)length
{
__block NSMutableString *newString = [NSMutableString string];
NSArray *components = [self componentsSeparatedByString:#" "];
if ([components count] > 0) {
NSString *lastWord = [components objectAtIndex:[components count]-1];
[components enumerateObjectsUsingBlock:^(NSString *obj, NSUInteger idx, BOOL *stop) {
if (([obj length]+[newString length] + [lastWord length] + 2) < length) {
[newString appendFormat:#" %#", obj];
} else {
[newString appendString:#"…"];
[newString appendFormat:#" %#", lastWord];
*stop = YES;
}
}];
}
return newString;
}
Usage:
NSString *string = #"Hello World! I am standing over here! Can you see me?";
NSLog(#"%#", [string stringByCuttingExceptLastWordWithLength:25]);
Suggestions:
make it a category method;
use NSCharacterSet and the built-in search methods rather than rolling your own.
So:
/* somewhere public */
#interface NSString (CutByWords)
- (NSString *)stringCutByWordsToMaxLength:(int)length
#end
/* in an implementation file, somewhere */
#implementation NSString (CutByWords)
// cut a string by words
- (NSString *)stringCutByWordsToMaxLength:(int)length
{
NSCharacterSet *whitespaceCharacterSet =
[NSCharacterSet whitespaceCharacterSet];
// to consider: a range check on length here?
NSRange relevantRange = NSMakeRange(0, length);
// find beginning of last word
NSRange lastWordRange =
[self rangeOfCharacterFromSet:whitespaceCharacterSet
options:NSBackwardsSearch
range:relevantRange];
// if the last word was the first word of the string,
// consume the whole string; this looks to be the same
// effect as the original scan forward given that the
// assumption is already made in the scan backwards that
// the string doesn't end on a whitespace; if I'm wrong
// then get [whitespaceCharacterSet invertedSet] and do
// a search forwards
if(lastWordRange.location == NSNotFound)
{
lastWordRange = relevantRange;
}
// adjust the range to include dependent chars
stringRange = [self rangeOfComposedCharacterSequencesForRange:stringRange];
// Now you can create the short string
NSString *string = [self substringWithRange:stringRange];
return [NSString stringWithFormat:#"%#...",string];
}
#end
/* subsequently */
NSString *string = ...whatever...;
NSString *cutString = [string stringCutByWordsToMaxLength:100];
So pretty much I want to check if my NSString from my NSArray is a substring of my string named imageName.
So lets say this:
My Image name is: picture5of-batman.png
My Array contains strings and one of them is: Batman
So pretty much I want to eliminate the: picture5of- part of the image name and replace it with the NSString from the NSArray.
This is how I try to do it but it never makes it to the if statement. And no my Array is not nil either. Here is the code:
for (NSString *string in superheroArray) {
if ([string rangeOfString:imageName].location != NSNotFound) {
//Ok so some string in superheroArray is equal to the file name of the image
imageName = [imageName stringByReplacingOccurrencesOfString:#"" withString:string
options:NSCaseInsensitiveSearch range:NSMakeRange(0, string.length)];
}
}
Edit1: This still does not work
for (NSString *string in superheroArray) {
if ([imageName rangeOfString:string options:NSCaseInsensitiveSearch].location != NSNotFound) {
//Ok so some string in superheroArray is equal to the file name of the image
imageName = string;
//HOW ABOUT THAT FOR EFFICIENCY :P
}
}
[imageName rangeOfString:string options: NSCaseInsensitiveSearch]
I don't see why it's not working in your code, maybe split the NSString stuff from the NSRage test.
but this work here :
NSArray *ar = [NSArray arrayWithObjects:#"Batman", #"Maurice", nil];
__block NSString *imageName = #"picture5of-batman.png";
__block NSUInteger theIndex = -1;
[ar enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
NSRange r = [imageName rangeOfString: obj
options: NSCaseInsensitiveSearch];
if (r.location != NSNotFound)
{
theIndex = idx;
NSString *str = [imageName pathExtension];
imageName = [(NSString *)obj stringByAppendingPathExtension:str];
// you found it, so you can stop now
*stop = YES;
}
}];
if (theIndex != -1)
{
NSLog(#"The index is : %d and new imageName == %#", theIndex, imageName);
}
And here is the NSLog statement :
2011-12-10 23:04:28.967 testSwitch1[2493:207] The index is : 0 and new imageName == Batman.png
I'm looking for the easiest way to convert a string from camelback format to Title Case format.
How do I change 'playerName' into 'Player Name'?
NSString *str = #"playerName";
NSMutableString *str2 = [NSMutableString string];
for (NSInteger i=0; i<str.length; i++){
NSString *ch = [str substringWithRange:NSMakeRange(i, 1)];
if ([ch rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]].location != NSNotFound) {
[str2 appendString:#" "];
}
[str2 appendString:ch];
}
NSLog(#"%#", str2.capitalizedString);
Here's a simpler Swift version. I've chucked it into an extension
extension String {
func stringFromCamelCase() -> String {
var string = self
string = string.stringByReplacingOccurrencesOfString("([a-z])([A-Z])", withString: "$1 $2", options: NSStringCompareOptions.RegularExpressionSearch, range: Range<String.Index>(start: string.startIndex, end: string.endIndex))
string.replaceRange(startIndex...startIndex, with: String(self[startIndex]).capitalizedString)
return string
}
}
Usage:
var str = "helloWorld"
str = str.stringFromCamelCase()
Try using a regex replace
NSString *modified = [input stringByReplacingOccurrencesOfString:#"([a-z])([A-Z])"
withString:#"$1 $2"
options:NSRegularExpressionSearch
range:NSMakeRange(0, input.length)];
A little shorter, using NSCharacterSet:
__block NSString *str = #"myVerySpecialPlayerName" ;
// split at uppercase letters
NSArray *splitString = [str componentsSeparatedByCharactersInSet:
[NSCharacterSet uppercaseLetterCharacterSet]] ;
// get the uppercase letters
NSArray *upperCaseLetters = [str componentsSeparatedByCharactersInSet:
[[NSCharacterSet uppercaseLetterCharacterSet] invertedSet]] ;
// join with two spaces
str = [splitString componentsJoinedByString:#" "] ;
__block NSInteger offset = 0 ;
// replace each second space with the missing uppercase letter
[upperCaseLetters enumerateObjectsUsingBlock:^(NSString *character, NSUInteger idx, BOOL *stop) {
if( [character length] > 0 ) {
str = [str stringByReplacingCharactersInRange:NSMakeRange(idx+offset+1, 1) withString:character] ;
offset += 2 ;
}
}] ;
// & capitalize the first one
str = [str capitalizedString] ;
NSLog(#"%#", str) ; // "My Very Special Player Name"
Trying to be more unicode compliant
extension String {
func camelCaseToTitleCase() -> String {
return unicodeScalars.map(replaceCaptialsWithSpacePlusCapital).joined().capitalized
}
private func replaceCaptialsWithSpacePlusCapital(unichar: UnicodeScalar) -> String {
if CharacterSet.uppercaseLetters.contains(unichar) {
return " \(unichar)"
}
return "\(unichar)"
}
}
I think you can tackle this problem with some Regular Expressions. Check out this similar question: iPhone dev: Replace uppercase characters in NSString with space and downcase
Although a little long, but this category for NSString should do the trick. It passed all my tests:
- (NSString *)splitOnCapital
{
// Make a index of uppercase characters
NSRange upcaseRange = NSMakeRange('A', 26);
NSIndexSet *upcaseSet = [NSIndexSet indexSetWithIndexesInRange:upcaseRange];
// Split our camecase word
NSMutableString *result = [NSMutableString string];
NSMutableString *oneWord = [NSMutableString string];
for (int i = 0; i < self.length; i++) {
char oneChar = [self characterAtIndex:i];
if ([upcaseSet containsIndex:oneChar]) {
// Found a uppercase char, now save previous word
if (result.length == 0) {
// First word, no space in beginning
[result appendFormat:#"%#", [oneWord capitalizedString]];
}else {
[result appendFormat:#" %#", oneWord];
}
// Clear previous word for new word
oneWord = [NSMutableString string];
}
[oneWord appendFormat:#"%c", oneChar];
}
// Add last word
if (oneWord.length > 0) {
[result appendFormat:#" %#", oneWord];
}
return result;
}
I had a similar issue, the answers here helped me create a solution. I had an array that had a list of labels I wanted to display within a UITableView, one label per row.
My issue was I parsed these labels out of an XML returned by a SOAP action and I had not idea over the format of the strings.
Firstly I implemented webstersx answer into a method. This was great but some of these labels began with a capital letter and some where camel case (e.g. some strings where exampleLabel and others where ExampleLabel. So this meant the ones beginning with a capital had a space inserted in front of the string.
I overcame this by trimming whitespaces from the beggining and end of the string using NSString's stringByTrimmingCharactersInSet.
The next issue was any abbreviations used, such as "ID" or "PNR Status", where being displayed as "I D" and "P N R Status" as the capital letters where, and quite rightly, being picked up and a space inserted before it.
I overcame this issue by implementing a regex similar to emdog4's answer into my new method.
Here is my completed solution:
- (NSString *)formatLabel:(NSString *)label
{
NSMutableString *str2 = [NSMutableString string];
for (NSInteger i=0; i<label.length; i++){
NSString *ch = [label substringWithRange:NSMakeRange(i, 1)];
if ([ch rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]].location != NSNotFound) {
[str2 appendString:#" "];
}
[str2 appendString:ch];
}
NSString * formattedString = [str2 stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]].capitalizedString;
formattedString = [formattedString stringByReplacingOccurrencesOfString:#"([A-Z]) (?![A-Z][a-z])" withString:#"$1" options:NSRegularExpressionSearch range:NSMakeRange(0, formattedString.length)];
return formattedString;
}
I then simply call something like this, for example, that will return my nicely formatted string:
NSString * formattedLabel = [self formatLabel:#"PNRStatus"];
NSLog(#"Formatted Label: %#", formattedLabel);
Will output:
2013-10-10 10:44:39.888 Test Project[28296:a0b] Formatted Label: PNR Status
If anyone needs a Swift version:
func camelCaseToTitleCase(s: NSString) -> String {
var newString = ""
if s.length > 0 {
newString = s.substringToIndex(1).uppercaseString
for i in 1..<s.length {
let char = s.characterAtIndex(i)
if NSCharacterSet.uppercaseLetterCharacterSet().characterIsMember(char) {
newString += " "
}
newString += s.substringWithRange(NSRange(location: i, length: 1))
}
}
return newString
}
while technically shorter, more ineffecient
NSString *challengeString = #"playerName";
NSMutableString *rStr = [NSMutableString stringWithString:challengeString];
while ([rStr rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]].location != NSNotFound) {
[rStr replaceCharactersInRange:[rStr rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]] withString:[[NSString stringWithFormat:#" %#", [rStr substringWithRange:[rStr rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]]]] lowercaseString]];
}
NSLog(#"%#", rStr.capitalizedString);
Not sure this is much shorter than websterx, but I find using characterIsMember easier to read and understand. Also added a length check to fix the space before if the string starts with a capital.
NSString *str = #"PlayerNameHowAboutALongerString";
NSMutableString *str2 = [NSMutableString string];
for (NSInteger i=0; i<str.length; i++){
unichar ch = [str characterAtIndex:i];
if ( [[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:ch]) {
if (str2.length > 0 ) {
[str2 appendString:#" "];
}
}
[str2 appendString:[NSString stringWithCharacters:&ch length:1]];
}
NSLog(#"--%#--", str2.capitalizedString);
The accepted answer didn't work for me because it doesn't capitalize the first letter, and if the first letter is already capitalized, it adds an extraneous space at the beginning. Here is my improved version:
- (NSString *)titleFromCamelCaseString:(NSString *)input
{
NSMutableString *output = [NSMutableString string];
[output appendString:[[input substringToIndex:1] uppercaseString]];
for (NSUInteger i = 1; i < [input length]; i++)
{
unichar character = [input characterAtIndex:i];
if ([[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:character])
{
[output appendString:#" "];
}
[output appendFormat:#"%C", character];
}
return output;
}
Here is Swift Code (objective c code by webstersx), Thanks !
var str: NSMutableString = "iLoveSwiftCode"
var str2: NSMutableString = NSMutableString()
for var i:NSInteger = 0 ; i < str.length ; i++ {
var ch:NSString = str.substringWithRange(NSMakeRange(i, 1))
if(ch .rangeOfCharacterFromSet(NSCharacterSet.uppercaseLetterCharacterSet()).location != NSNotFound) {
str2 .appendString(" ")
}
str2 .appendString(ch)
}
println("\(str2.capitalizedString)")
}
NSString *input = #"playerName";
NSString *modified = [input stringByReplacingOccurrencesOfString:#"(?<!^)[A-Z]" withString:#" $0" options:NSRegularExpressionSearch range:NSMakeRange(0, input.length)].capitalizedString;
Another solution under Swift 2.2
extension String {
var stringFromCamelCase:String {
return (self as NSString).replacingOccurrences(
of: "([a-z])([A-Z])",
with: "$1 $2",
options: CompareOptions.regularExpressionSearch,
range: NSMakeRange(0, self.characters.count)
).uppercaseFirst
}
var uppercaseFirst: String {
return String(characters.prefix(1)).uppercased() + String(characters.dropFirst()).lowercased()
}
}
try using:
string.Split()
then use the cap letter as token
I'm looking for a simple, efficient way to convert strings in CamelCase to underscore notation (i.e., MyClassName -> my_class_name) and back again in Objective C.
My current solution involves lots of rangeOfString, characterAtIndex, and replaceCharactersInRange operations on NSMutableStrings, and is just plain ugly as hell :) It seems that there must be a better solution, but I'm not sure what it is.
I'd rather not import a regex library just for this one use case, though that is an option if all else fails.
Chris's suggestion of RegexKitLite is good. It's an excellent toolkit, but this could be done pretty easily with NSScanner. Use -scanCharactersFromSet:intoString: alternating between +uppercaseLetterCharacterSet and +lowercaseLetterCharacterSet. For going back, you'd use -scanUpToCharactersFromSet: instead, using a character set with just an underscore in it.
How about these:
NSString *MyCamelCaseToUnderscores(NSString *input) {
NSMutableString *output = [NSMutableString string];
NSCharacterSet *uppercase = [NSCharacterSet uppercaseLetterCharacterSet];
for (NSInteger idx = 0; idx < [input length]; idx += 1) {
unichar c = [input characterAtIndex:idx];
if ([uppercase characterIsMember:c]) {
[output appendFormat:#"_%#", [[NSString stringWithCharacters:&c length:1] lowercaseString]];
} else {
[output appendFormat:#"%C", c];
}
}
return output;
}
NSString *MyUnderscoresToCamelCase(NSString *underscores) {
NSMutableString *output = [NSMutableString string];
BOOL makeNextCharacterUpperCase = NO;
for (NSInteger idx = 0; idx < [underscores length]; idx += 1) {
unichar c = [underscores characterAtIndex:idx];
if (c == '_') {
makeNextCharacterUpperCase = YES;
} else if (makeNextCharacterUpperCase) {
[output appendString:[[NSString stringWithCharacters:&c length:1] uppercaseString]];
makeNextCharacterUpperCase = NO;
} else {
[output appendFormat:#"%C", c];
}
}
return output;
}
Some drawbacks are that they do use temporary strings to convert between upper and lower case, and they don't have any logic for acronyms, so myURL will result in my_u_r_l.
Try this magic:
NSString* camelCaseString = #"myBundleVersion";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"(?<=[a-z])([A-Z])|([A-Z])(?=[a-z])" options:0 error:nil];
NSString *underscoreString = [[regex stringByReplacingMatchesInString:camelCaseString options:0 range:NSMakeRange(0, camelCaseString.length) withTemplate:#"_$1$2"] lowercaseString];
NSLog(#"%#", underscoreString);
Output: my_bundle_version
If your concern is just the visibility of your code, you could make a category for NSString using the methods you've designed already. That way, you only see the ugly mess once. ;)
For instance:
#interface NSString(Conversions) {
- (NSString *)asCamelCase;
- (NSString *)asUnderscored;
}
#implementation NSString(Conversions) {
- (NSString *)asCamelCase {
// whatever you came up with
}
- (NSString *)asUnderscored {
// whatever you came up with
}
}
EDIT: After a quick Google search, I couldn't find any way of doing this, even in plain C. However, I did find a framework that could be useful. It's called RegexKitLite. It uses the built-in ICU library, so it only adds about 20K to the final binary.
Here's my implementation of Rob's answer:
#implementation NSString (CamelCaseConversion)
// Convert a camel case string into a dased word sparated string.
// In case of scanning error, return nil.
// Camel case string must not start with a capital.
- (NSString *)fromCamelCaseToDashed {
NSScanner *scanner = [NSScanner scannerWithString:self];
scanner.caseSensitive = YES;
NSString *builder = [NSString string];
NSString *buffer = nil;
NSUInteger lastScanLocation = 0;
while ([scanner isAtEnd] == NO) {
if ([scanner scanCharactersFromSet:[NSCharacterSet lowercaseLetterCharacterSet] intoString:&buffer]) {
builder = [builder stringByAppendingString:buffer];
if ([scanner scanCharactersFromSet:[NSCharacterSet uppercaseLetterCharacterSet] intoString:&buffer]) {
builder = [builder stringByAppendingString:#"-"];
builder = [builder stringByAppendingString:[buffer lowercaseString]];
}
}
// If the scanner location has not moved, there's a problem somewhere.
if (lastScanLocation == scanner.scanLocation) return nil;
lastScanLocation = scanner.scanLocation;
}
return builder;
}
#end
Here's yet another version based on all the above. This version handles additional forms. In particular, tested with the following:
camelCase => camel_case
camelCaseWord => camel_case_word
camelURL => camel_url
camelURLCase => camel_url_case
CamelCase => camel_case
Here goes
- (NSString *)fromCamelCaseToDashed3 {
NSMutableString *output = [NSMutableString string];
NSCharacterSet *uppercase = [NSCharacterSet uppercaseLetterCharacterSet];
BOOL previousCharacterWasUppercase = FALSE;
BOOL currentCharacterIsUppercase = FALSE;
unichar currentChar = 0;
unichar previousChar = 0;
for (NSInteger idx = 0; idx < [self length]; idx += 1) {
previousChar = currentChar;
currentChar = [self characterAtIndex:idx];
previousCharacterWasUppercase = currentCharacterIsUppercase;
currentCharacterIsUppercase = [uppercase characterIsMember:currentChar];
if (!previousCharacterWasUppercase && currentCharacterIsUppercase && idx > 0) {
// insert an _ between the characters
[output appendString:#"_"];
} else if (previousCharacterWasUppercase && !currentCharacterIsUppercase) {
// insert an _ before the previous character
// insert an _ before the last character in the string
if ([output length] > 1) {
unichar charTwoBack = [output characterAtIndex:[output length]-2];
if (charTwoBack != '_') {
[output insertString:#"_" atIndex:[output length]-1];
}
}
}
// Append the current character lowercase
[output appendString:[[NSString stringWithCharacters:¤tChar length:1] lowercaseString]];
}
return output;
}
If you are concerned with the speed of your code you probably want to write a more performant version of the code:
- (nonnull NSString *)camelCaseToSnakeCaseString {
if ([self length] == 0) {
return #"";
}
NSMutableString *output = [NSMutableString string];
NSCharacterSet *digitSet = [NSCharacterSet decimalDigitCharacterSet];
NSCharacterSet *uppercaseSet = [NSCharacterSet uppercaseLetterCharacterSet];
NSCharacterSet *lowercaseSet = [NSCharacterSet lowercaseLetterCharacterSet];
for (NSInteger idx = 0; idx < [self length]; idx += 1) {
unichar c = [self characterAtIndex:idx];
// if it's the last one then just append lowercase of character
if (idx == [self length] - 1) {
if ([uppercaseSet characterIsMember:c]) {
[output appendFormat:#"%#", [[NSString stringWithCharacters:&c length:1] lowercaseString]];
}
else {
[output appendFormat:#"%C", c];
}
continue;
}
unichar nextC = [self characterAtIndex:(idx+1)];
// this logic finds the boundaries between lowercase/uppercase/digits and lets the string be split accordingly.
if ([lowercaseSet characterIsMember:c] && [uppercaseSet characterIsMember:nextC]) {
[output appendFormat:#"%#_", [[NSString stringWithCharacters:&c length:1] lowercaseString]];
}
else if ([lowercaseSet characterIsMember:c] && [digitSet characterIsMember:nextC]) {
[output appendFormat:#"%#_", [[NSString stringWithCharacters:&c length:1] lowercaseString]];
}
else if ([digitSet characterIsMember:c] && [uppercaseSet characterIsMember:nextC]) {
[output appendFormat:#"%#_", [[NSString stringWithCharacters:&c length:1] lowercaseString]];
}
else {
// Append lowercase of character
if ([uppercaseSet characterIsMember:c]) {
[output appendFormat:#"%#", [[NSString stringWithCharacters:&c length:1] lowercaseString]];
}
else {
[output appendFormat:#"%C", c];
}
}
}
return output;
}
I have combined the answers found here into my refactoring library, es_ios_utils. See NSCategories.h:
#property(nonatomic, readonly) NSString *asCamelCaseFromUnderscores;
#property(nonatomic, readonly) NSString *asUnderscoresFromCamelCase;
Usage:
#"my_string".asCamelCaseFromUnderscores
yields #"myString"
Please push improvements!
I happened upon this question looking for a way to convert Camel Case to a spaced, user displayable string. Here is my solution which worked better than replacing #"_" with #" "
- (NSString *)fromCamelCaseToSpaced:(NSString*)input {
NSCharacterSet* lower = [NSCharacterSet lowercaseLetterCharacterSet];
NSCharacterSet* upper = [NSCharacterSet uppercaseLetterCharacterSet];
for (int i = 1; i < input.length; i++) {
if ([upper characterIsMember:[input characterAtIndex:i]] &&
[lower characterIsMember:[input characterAtIndex:i-1]])
{
NSString* soFar = [input substringToIndex:i];
NSString* left = [input substringFromIndex:i];
return [NSString stringWithFormat:#"%# %#", soFar, [self fromCamelCaseToSpaced:left]];
}
}
return input;
}
OK guys. Here is an all regex answer, which I consider the only true way:
Given:
NSString *MYSTRING = "foo_bar";
NSRegularExpression *_toCamelCase = [NSRegularExpression
regularExpressionWithPattern:#"(_)([a-z])"
options:NSRegularExpressionCaseInsensitive error:&error];
NSString *camelCaseAttribute = [_toCamelCase
stringByReplacingMatchesInString:MYSTRING options:0
range:NSMakeRange(0, attribute.length)
withTemplate:#"\\U$2"];
Yields fooBar.
Conversely:
NSString *MYSTRING = "fooBar";
NSRegularExpression *camelCaseTo_ = [NSRegularExpression
regularExpressionWithPattern:#"([A-Z])"
options:0 error:&error];
NSString *underscoreParsedAttribute = [camelCaseTo_
stringByReplacingMatchesInString:MYSTRING
options:0 range:NSMakeRange(0, attribute.length)
withTemplate:#"_$1"];
underscoreParsedAttribute = [underscoreParsedAttribute lowercaseString];
Yields: foo_bar.
\U$2 replaces second capture group with upper-case version of itself :D
\L$1 however, oddly, does not replace the first capture group with a lower-case version of itself :( Not sure why, it should work. :/