NSString - how to go from "ÁlgeBra" to "Algebra"

Question

Does anyone knows hoe to get a NSString like "ÁlgeBra" to "Algebra", without the accent, and capitalize only the first letter?

Thanks,

RL

score 56 · Answer 1 · edited May 23 '17 at 10:27

56

dreamlax has already mentioned the capitalizedString method. Instead of doing a lossy conversion to and from NSData to remove the accented characters, however, I think it is more elegant to use the stringByFoldingWithOptions:locale: method.

NSString *accentedString = @"ÁlgeBra";
NSString *unaccentedString = [accentedString stringByFoldingWithOptions:NSDiacriticInsensitiveSearch locale:[NSLocale currentLocale]];
NSString *capitalizedString = [unaccentedString capitalizedString];

Depending on the nature of the strings you want to convert, you might want to set a fixed locale (e.g. English) instead of using the user's current locale. That way, you can be sure to get the same results on every machine.

edited May 23 '17 at 10:27

Community

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answered Feb 19 '11 at 12:35

Ole Begemann

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*This* is the correct answer. Don't do the silly NSData <-> NSString business that dreamlax suggests. – thefaj Jul 30 '12 at 22:48
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The allowLossyConversion technique did handle some scenarios that I couldn't do with NSLocale. For exmaple if I have the following string: ßÄÆûñ. When I run the stringByFoldingWithOptions I get: ßAÆun. When I run the allowLossyConversion I get: sAAEun. In my case I want the second option. Is there a way to get a similar answer using less of a hack? – Alex Sep 28 '12 at 18:59
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@Alex: It's not a hack, Apple recommend the `allowLossyConversion` approach in their documentation to transform an ellipsis character to three ASCII periods. @thefaj inappropriately named this technique wrong but it is in fact a legitimate approach. – dreamlax Oct 10 '12 at 03:27
What would happen if you passed in Japanese, Arabic, Chinese, etc. characters into the allowLossyConversion technique? You certainly don't want to convert them to ASCII strings. – Tap Forms Oct 20 '12 at 21:09
@TapForms: That depends on the desired result. – dreamlax Oct 22 '12 at 10:39
@dreamlax -- You are wrong, and your method is incorrect, hackey, and poor style. Use Ole's method as described above. --- To the other developers reading this, vote this answer up and dreamlax's down. – thefaj Nov 13 '12 at 00:57
@thefaj: Then why is it on [**Apple's own documentation**](https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Strings/Articles/CreatingStrings.html) as a method of collapsing certain Unicode characters to ASCII? – dreamlax Nov 13 '12 at 03:20
Sometimes you _do_ want lossy conversion, like filenames that don't accept Japanese, Chinese, emoji, etc. So it really depends on the desired result as @dreamlax said – leonaka May 27 '17 at 00:52

dreamlax · Accepted Answer · 2011-02-19T11:48:35.460

13

NSString has a method called capitalizedString:

Return Value

A string with the first character from each word in the receiver changed to its corresponding uppercase value, and all remaining characters set to their corresponding lowercase values.

NSString *str = @"AlgeBra";
NSString *other = [str capitalizedString];

NSLog (@"Old: %@, New: %@", str, other);

Edit:

Just saw that you would like to remove accents as well. You can go through a series of steps:

// original string
NSString *str = @"ÁlgeBra";

// convert to a data object, using a lossy conversion to ASCII
NSData *asciiEncoded = [str dataUsingEncoding:NSASCIIStringEncoding
                         allowLossyConversion:YES];

// take the data object and recreate a string using the lossy conversion
NSString *other = [[NSString alloc] initWithData:asciiEncoded
                                        encoding:NSASCIIStringEncoding];
// relinquish ownership
[other autorelease];

// create final capitalized string
NSString *final = [other capitalizedString];

The documentation for dataUsingEncoding:allowLossyConversion: explicitly says that the letter ‘Á’ will convert to ‘A’ when converting to ASCII.

edited Feb 19 '11 at 11:48

answered Feb 19 '11 at 11:32

dreamlax

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Don't do this. It is wrong -- See Ole Begemann's response below. – thefaj Jul 30 '12 at 22:48
When I try this I get a "?" character instead of the "OE" as expected. I'm testing this on iOS 6. Has anyone had any luck with this technique? – Tap Forms Oct 22 '12 at 08:52
@TapForms: File a bug at Apple. It works with Æ so there's no reason it shouldn't work with Œ. – dreamlax Oct 22 '12 at 10:38
@dreamlax Yes, it must be a bug. I just tested your code with this string: @"Œ Æ ß" and this is the result I got: "? AE s". The OE is coming out wrong. I may just have to add a special case for OE and file a bug. – Tap Forms Oct 22 '12 at 16:57
This method worked perfectly for me to convert city names for searching. Gdańsk to Gdansk, Córdoba to Cordoba – Tom Kincaid May 03 '14 at 12:22

score 1 · Answer 3 · edited Aug 11 '16 at 12:19

Here's a step by step example of how to do it. There's room for improvement, but you get the basic idea......

NSString *input = @"ÁlgeBra";
NSString *correctCase = [NSString stringWithFormat:@"%@%@",
                           [[input substringToIndex:1] uppercaseString],
                           [[input substringFromIndex:1] lowercaseString]];

NSString *result = [[[NSString alloc] initWithData:[correctCase dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES] encoding:NSASCIIStringEncoding] autorelease];

NSLog( @"%@", result );

NSString - how to go from "ÁlgeBra" to "Algebra"

3 Answers3

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