I have a string which I want to insert to an ObjC NSURL.UrlWithString function, but it has to be without any quotes.
bad example:
$.NSURL.URLWithString("http://192.168.1.1")
In JavaScript, I know I can do something like StringFromCharCode(34,90,81,33) to avoid quotes, but what is the alternative in Objective C? (not Swift).
JS String.fromCharCode()
Documentation:
The static String.fromCharCode() method returns a string created from the specified sequence of UTF-16 code units.
console.log(String.fromCharCode(189, 43, 190, 61));
// expected output: "½+¾="
Obj-C NSString
+ (instancetype)stringWithCharacters:(const unichar *)characters
length:(NSUInteger)length;
Documentation:
Returns a string containing a given number of characters taken from a given C array of UTF-16 code units.
Example
unichar chars[] = {189, 43, 190, 61};
NSString *s = [NSString stringWithCharacters:chars
length:sizeof(chars) / sizeof(unichar)];
NSLog(#"%#", s);
// expected output: ½+¾=
Do you know C's printf syntax? Then use something similar with characters
[NSString stringWithFormat:#"%c%c%c%c", 34, 90, 81, 33];
or repeatedly append to a (mutable) string one string at a time you create like this with a character.
NSString * s1 = [NSString stringWithFormat:#"%c", c];
Related
I have a file, which I'm reading into an NSString object using stringWithContentsOfFile. It contains Unicode for Japanese characters such as:
\u305b\u3044\u3075\u304f
which I believe is
せいふく
I would like my NSString object to store the string as the latter, but it is storing it as the former.
The thing I don't quite understand is that when I do this:
NSString *myString = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
It stores it as: \u305b\u3044\u3075\u304f.
But when I hardcode in the string:
NSString *myString = #"\u305b\u3044\u3075\u304f";
It correctly converts it and stores it as: せいふく
Does stringWIthContentsOfFile escape the Unicode in some way? Any help will be appreciated.
Thanks.
In the file \u305b\u3044\u3075\u304f are just normal characters. So you are getting them in string. You need to save actual Japanese characters in the file. That is, store せいふく in file and that will be loaded in the string.
You can try this, dont know how feasible it is..
NSArray *unicodeArray = [stringFromFile componentsSeparatedByString:#"\\u"];
NSMutableString *finalString = [[NSMutableString alloc] initWithString:#""];
for (NSString *unicodeString in unicodeArray) {
if (![unicodeString isEqualToString:#""]) {
unichar codeValue;
[[NSScanner scannerWithString:unicodeString] scanHexInt:&codeValue];
NSString* betaString = [NSString stringWithCharacters:&codeValue length:1];
[finalString appendString:betaString];
}
}
//finalString should have せいふく
Something like \u305b in an Objective-C string is in fact an instruction to the compiler to replace it with the actual UTF-8 byte sequence for that character. The method reading the file is not a compiler, and only reads the bytes it finds. So to get that character (officially called "code point"), your file must contain the actual UTF-8 byte sequence for that character, and not the symbolic representation \u305b.
It's a bit like \x43. This is, in your source code, four characters, but it is replaced by one byte with value 0x43. So if you write #"\x43" to a file, the file will not contain the four characters '\', 'x', '4', '3', it will contain the single character 'C' (which has ASCII value 0x43).
I have an int, for example say 45. I want to get NSString from this int padded with 4 zeroes. So the result would be : #"0045". Similar, if the int is 9, I want to get: #"0009".
I know I can count the number of digits, then subtract it from how many zeroes i want padded, and prepend that number to the string, but is there a more elegant way? Thanks.
Try this:
NSLog(#"%04d", 45);
NSLog(#"%04d", 9);
If it works, then you can get padded number with
NSString *paddedNumber = [NSString stringWithFormat:#"%04d", 45];
NSString *otherPaddedNumber = [NSString stringWithFormat:#"%04d", 9];
Update
If you want to have arbitrary number you'd have to create a format for your format:
// create "%04d" format string
NSString *paddingFormat = [NSString stringWithFormat:#"%%0%dd", 4];
// use it for padding numbers
NSString *paddedNumber = [NSString stringWithFormat:paddingFormat, 45];
NSString *otherPaddedNumber = [NSString stringWithFormat:paddingFormat, 9];
Update 2
Please see #Ibmurai's comment on how to properly pad a number with NSLog.
Excuse me for answering this question with an already accepted answer, but the answer (in the update) is not the best solution.
If you want to have an arbitrary number you don't have to create a format for your format, as IEEE printf supports this. Instead do:
NSString *paddedNumber = [NSString stringWithFormat:#"%0*d", 4, 45];
NSString *otherPaddedNumber = [NSString stringWithFormat:#"%0*d", 4, 9];
While the other solution works, it is less effective and elegant.
From the IEEE printf specification:
A field width, or precision, or both, may be indicated by an asterisk ( '*' ). In this case an argument of type int supplies the field width or precision.
Swift version as Int extension (one might wanna come up with a better name for that method):
extension Int
{
func zeroPaddedStringValueForFieldWidth(fieldWidth: Int) -> String
{
return String(format: "%0*d", fieldWidth, self)
}
}
Examples:
print( 45.zeroPaddedStringValueForFieldWidth(4) ) // prints "0045"
print( 9.zeroPaddedStringValueForFieldWidth(4) ) // prints "0009"
i am a beginer in objective c.i found the following line in code and is not able to understand what it does it do, as storeselect has not been used anywhere in the code.
NSString *storeSelect=#"";
Objective-C builds on C language. In C, quotes are placed around string literals, i.e. "hello". To distinguish NSString and C strings (char pointers, char *), Objective-C uses # in front of strings, so #"" is simply empty NSString. If there was no #, it would be empty C string, e.g. char *myString = "hello world";.
storeSelect is the name of a variable whose type is NSString *, with the value assigned to #""
It's just assigning an empty string to a variable named storeSelect. The #"" is for constant strings.
NSString *storeSelect=#"Hello World";
is a shortcut of -
NSString *str = [NSString stringWithCString:"Hello World"];
as "stringWithCString" is convenience method it will be automatically adds autoreleased.
How do I convert a char to an NSString in Objective-C?
Not a null-terminated C string, just a simple char c = 'a'.
You can use stringWithFormat:, passing in a format of %c to represent a character, like this:
char c = 'a';
NSString *s = [NSString stringWithFormat:#"%c", c];
You can make a C-string out of one character like this:
char cs[2] = {c, 0}; //c is the character to convert
NSString *s = [[NSString alloc] initWithCString:cs encoding: SomeEncoding];
Alternatively, if the character is known to be an ASCII character (i. e. Latin letter, number, or a punctuation sign), here's another way:
unichar uc = (unichar)c; //Just extend to 16 bits
NSString *s = [NSString stringWithCharacters:&uc length:1];
The latter snippet with surely fail (not crash, but produce a wrong string) with national characters. For those, simple extension to 16 bits is not a correct conversion to Unicode. That's why the encoding parameter is needed.
Also note that the two snippets above produce a string with diferent deallocation requirements. The latter makes an autoreleased string, the former makes a string that needs a [release] call.
I want the user to input a string and then assign the input to an NSString. Right now my code looks like this:
NSString *word;
scanf("%s", &word);
The scanf function reads into a C string (actually an array of char), like this:
char word[40];
int nChars = scanf("%39s", word); // read up to 39 chars (leave room for NUL)
You can convert a char array into NSString like this:
NSString* word2 = [NSString stringWithBytes:word
length:nChars
encoding:NSUTF8StringEncoding];
However scanf only works with console (command line) programs. If you're trying to get input on a Mac or iOS device then scanf is not what you want to use to get user input.
scanf does not work with any object types. If you have a C string and want to create an NSString from it, use -[NSString initWithBytes:length:encoding:].
scanf does not work with NSString as scanf doesn’t work on objects. It works only on primitive datatypes such as:
int
float
BOOL
char
What to do?
Technically a string is made up of a sequence of individual characters. So to accept string input, you can read in the sequence of characters and convert it to a string.
use:
[NSString stringWithCString:cstring encoding:1];
Here is a working example:
NSLog(#"What is the first name?");
char cstring[40];
scanf("%s", cstring);
firstName = [NSString stringWithCString:cstring encoding:1];
Here’s an explanation of the above code, comment by comment:
You declare a variable called cstring to hold 40 characters.
You then tell scanf to expect a list of characters by using the %s format specifier.
Finally, you create an NSString object from the list of characters that were read in.
Run your project; if you enter a word and hit Enter, the program should print out the same word you typed. Just make sure the word is less than 40 characters; if you enter more, you might cause the program to crash — you are welcome to test that out yourself! :]
Taken from: RW.
This is how I'd do it:
char word [40];
scanf("%s",word);
NSString * userInput = [[NSString alloc] initWithCString: word encoding: NSUTF8StringEncoding];
yes, but sscanf does, and may be a good solution for complex NSString parsing.
Maybe this will work for you because it accepts string with spaces as well.
NSLog(#"Enter The Name Of State");
char name[20];
gets(name);
NSLog(#"%s",name);
Simple Solution is
char word[40];
scanf("%39s", word);
NSString* word2 = [NSString stringWithUTF8String:word];
The NSFileHandle class is an object-oriented wrapper for a file descriptor. For files, you can read, write, and seek within the file.
NSFileHandle *inputFile = [NSFileHandle fileHandleWithStandardInput];
NSData *inputData = [inputFile availableData];
NSString *word = [[NSString alloc]initWithData:inputData encoding:NSUTF8StringEncoding];