NSString to NSData Example

how to convert NSString to NSData with Objective-C.
NSString – holds text data.
NSData   – holds binary data

We can use -[NSString dataUsingEncoding] function to convert NSString to NSData.
Sytax:

- (NSData *)dataUsingEncoding:(NSStringEncoding)encoding allowLossyConversion:(BOOL)flag;
- (NSData *)dataUsingEncoding:(NSStringEncoding)encoding;

if allowLossyConversion is YES, characters are removed/altered in conversion.

List of Encoding supported by NSString.

enum {
    NSASCIIStringEncoding = 1,      /* 0..127 only */
    NSNEXTSTEPStringEncoding = 2,
    NSJapaneseEUCStringEncoding = 3,
    NSUTF8StringEncoding = 4,
    NSISOLatin1StringEncoding = 5,
    NSSymbolStringEncoding = 6,
    NSNonLossyASCIIStringEncoding = 7,
    NSShiftJISStringEncoding = 8,          /* kCFStringEncodingDOSJapanese */
    NSISOLatin2StringEncoding = 9,
    NSUnicodeStringEncoding = 10,
    NSWindowsCP1251StringEncoding = 11,    /* Cyrillic; same as AdobeStandardCyrillic */
    NSWindowsCP1252StringEncoding = 12,    /* WinLatin1 */
    NSWindowsCP1253StringEncoding = 13,    /* Greek */
    NSWindowsCP1254StringEncoding = 14,    /* Turkish */
    NSWindowsCP1250StringEncoding = 15,    /* WinLatin2 */
    NSISO2022JPStringEncoding = 21,        /* ISO 2022 Japanese encoding for e-mail */
    NSMacOSRomanStringEncoding = 30,

    NSUTF16StringEncoding = NSUnicodeStringEncoding,      /* An alias for NSUnicodeStringEncoding */

    NSUTF16BigEndianStringEncoding = 0x90000100,          /* NSUTF16StringEncoding encoding with explicit endianness specified */
    NSUTF16LittleEndianStringEncoding = 0x94000100,       /* NSUTF16StringEncoding encoding with explicit endianness specified */

    NSUTF32StringEncoding = 0x8c000100,                   
    NSUTF32BigEndianStringEncoding = 0x98000100,          /* NSUTF32StringEncoding encoding with explicit endianness specified */
    NSUTF32LittleEndianStringEncoding = 0x9c000100        /* NSUTF32StringEncoding encoding with explicit endianness specified */
};

NSString to NSData Example

NSString * str =@"ABCD";
NSData * data =[str dataUsingEncoding:NSUTF8StringEncoding]; //Data
NSLog(@"Data =%@",data);

Output:

 Data =<41424344>

 // HEX 41 -> A , 42 -> B , 43 ->C , 44->D

Reference :NSString Documentation