unichar data[6] = {97,98,99,100,101,102};
//Initialize the string with an array of Unicode values
NSString* str = [[NSString alloc]initWithCharacters:data length:6];
NSLog(@"%@",str);
//Convert C-style strings to NSString objects
char* cstr = "Hello,iOS!";
NSString* str2 = [NSString stringWithUTF8String:cstr];
NSLog(@"%@",str2);
//write the string to the specified file
[str2 writeToFile:@"myFile.txt" atomically:YES encoding:NSUTF8StringEncoding error:nil];
//Read the file content, initialize the string with the file content
NSString* str3 = [NSString stringWithContentsOfFile:@"myFile.txt" encoding:NSUTF8StringEncoding error:nil];
NSLog(@"%@",str3);
NSString* str4 = @"hello";
NSString* str5 = @" word";
//Append a fixed string after str
str4 = [str4 stringByAppendingString:str5];
NSLog(@"%@",str4);
const char*conStr= [str4 UTF8String];
NSLog ( @"Get the C-style string for the C string: %s" ,conStr);
NSLog ( @"str is decoded according to UTF-8 character set: %lu" ,[str4 lengthOfBytesUsingEncoding :NSUTF8StringEncoding]);
NSLog ( @"Get the string consisting of the first 10 characters of str: %@" ,[str4 substringToIndex: 10 ]);
NSLog ( @"Get str starting from the 5th character, to the following string:%@" ,[str4 substringFromIndex: 5 ]);
//[str substringWithRange:NSMakeRange(5,3)] starts from the 5th and intercepts 3 lengths
NSLog ( @"Get the string from the 5th character to the 10th character:%@" ,[str4 substringWithRange:NSMakeRange( 5 , 3 )]);
//Get the position of hello in the character
NSRange range = [str4 rangeOfString:@"hello"];
NSLog ( @"Get the position of hello in the character:%ld,length:%ld" ,range.location,range.length);
//Convert str characters to uppercase
str4 = [str4 uppercaseString];
NSLog(@"%@",str4);
===============================================
NSString* str = @" word";
NSMutableString* MTStr = [NSMutableStringstringWithFormat:@"Hello"];
// Append fixed string
[MTStr appendString:str];
NSLog(@"%@",MTStr);
// Append string with variable
[MTStr appendFormat:@"%@",@"呵呵呵"];
NSLog(@"%@",MTStr);
// Append the string at the specified position
[MTStr insertString:@"OOO" atIndex:5];
NSLog(@"%@",MTStr);
// delete all strings from position 5 to position 8
[MTStr deleteCharactersInRange:NSMakeRange(5, 3)];
NSLog(@"%@",MTStr);
//Replace "hehehe" with "!!!"
[MTStr replaceCharactersInRange:NSMakeRange(10, 3) withString:@"!!!"];
NSLog(@"%@",MTStr);