Summary of the methods in Objective C that manipulate strings using the NSString class

1. String cutting
1. String with nodes, such as "@" < p > Nasty node < br/ > < /p > "We only want the Chinese in the middle

Treatment:

NSString *string1 = @"<p> Nasty node <br/></p>";

 

/* Put all the unwanted characters in here characterSet1 There is no need to add additional commas or Spaces unless there is a space you want to remove from the string, as shown here < p / And so on exist separately, not as a whole character */

 

NSCharacterSet *characterSet1 = [NSCharacterSet characterSetWithCharactersInString:@"<p/brh>"];

 

//  will string1 According to the characterSet1 Is divided into an array 

 

NSArray *array1 = [string1 componentsSeparatedByCharactersInSet:characterSet1];

 

NSLog(@"array = %@",array1);

 

for(NSString *string1 in array1)

{

    if ([string1 length]>0) {

         

        //  here string Is a Chinese string 

 

        NSLog(@"string = %@",string1);

    }

}

Print result:

2016-01-17 10:55:34.017 string[17634:303] 
array = (
 "",
 "",
 "",
 "\U8ba8\U538c\U7684\U8282\U70b9",
 "",
 "",
 "",
 "",
 "",
 "",
 "",
 "",
 ""
)
2016-01-17 10:55:34.049 string[17634:303] 
string =  Nasty node 

2. A string with Spaces, such as

@hello world remove Spaces

NSString *string2 = @"hello world";

 

/* Processing the blank space */

 

NSCharacterSet *characterSet2 = [NSCharacterSet whitespaceCharacterSet];

 

//  will string1 According to the characterSet1 Is divided into an array 

NSArray *array2 = [string2 componentsSeparatedByCharactersInSet:characterSet2];

 

NSLog(@"\narray = %@",array2);

 

//  To hold the processed string 

NSMutableString *newString1 = [NSMutableString string];

 

for(NSString *string in array1)

{

    [newString1 appendString:string];

}

NSLog(@"newString = %@", newString1);

Print result:

2016-01-17 11:02:49.656 string[17889:303] 
array = (
 hello,
 world
)
2016-01-17 11:02:49.657 string[17889:303] newString = helloworld

PS: to handle other elements such as letters, simply change the value of NSCharacterSet.

+ (id)controlCharacterSet;

 

+ (id)whitespaceCharacterSet;

 

+ (id)whitespaceAndNewlineCharacterSet;

 

+ (id)decimalDigitCharacterSet;

 

+ (id)letterCharacterSet;

 

+ (id)lowercaseLetterCharacterSet;

 

+ (id)uppercaseLetterCharacterSet;

 

+ (id)nonBaseCharacterSet;

 

+ (id)alphanumericCharacterSet;

 

+ (id)decomposableCharacterSet;

 

+ (id)illegalCharacterSet;

 

+ (id)punctuationCharacterSet;

 

+ (id)capitalizedLetterCharacterSet;

 

+ (id)symbolCharacterSet;

 

+ (id)newlineCharacterSet NS_AVAILABLE(10_5, 2_0);

 

+ (id)characterSetWithRange:(NSRange)aRange;

 

+ (id)characterSetWithCharactersInString:(NSString *)aString;

 

+ (id)characterSetWithBitmapRepresentation:(NSData *)data;

 

+ (id)characterSetWithContentsOfFile:(NSString *)fName;

2. Concatenate the elements in NSArray with the characters

NSArray *array = [NSArray arrayWithObjects:@"hello",@"world",nil];

 

// If you want to use ,: String concatenation, just put the following @" " A space for @"," or @":" Can be 

NSString *string = [array componentsJoinedByString:@" "];

 

NSLog(@"string = %@",string);

Print result:

hello world

3. Intercept substrings:

Here is an example of getting the time. When you get the current time with NSDate, sometimes you only need a date or only a time

1. Intercepts from the beginning of a string to the specified location, such as

// Gets the current date and time     

NSDate *date = [NSDate date];

         

// Define date format , I won't focus here NSDate , which will be discussed in more detail later        

NSDateFormatter *dateformatter = [[NSDateFormatter alloc] init];

         

// Set the date format         

[dateformatter setDateFormat:@"YYYY-MM-dd HH:mm"];

         

// Convert the date to NSString type       

NSString *string = [dateformatter stringFromDate:date];

NSLog(@"\ncurrent = %@",string);

                

// Capture the date substringToIndex 

NSString *currentDate = [string substringToIndex:10];

                 

NSLog(@"\ncurrentDate = %@",currentDate);

Print result:

current = 2016-01-1711:12


currentDate = 2016-01-17

2. Extract the middle substring -substringWithRange

// Intercept, 

NSString *currentMonthAndDate = [string substringWithRange:[NSMakeRange(5, 5)]];

         

NSLog(@"currentMonthAndDate = %@",currentMonthAndDate);

Print result:

currentMonthAndDate = 06-27

3. Intercept -substringFromIndex from a certain position

// The interception time substringFromIndex

NSString *currentTime = [string substringFromIndex:11];

         

NSLog(@"\ncurrentTime = %@",currentTime);\

Print result:

currentTime = 11:25

4. Compare strings

NSString *first = @"string";

NSString *second = @"String";

1. Determine whether the two strings are the same -isEqualToString method

BOOL isEqual = [first isEqualToString:second];

 

NSLog(@"first is Equal to second:%@",isEqual);

Print result:

first is Equal to second:0

2. The compare method compares three values of the string

NSOrderedSame// Whether or not the same 

NSOrderedAscending// Ascending, in alphabetical order, greater than is true 

NSOrderedDescending// In descending order, in alphabetical order, less than is true 
BOOL result = [first compare:sencond] == NSOrderedSame;    

NSLog(@"result:%d",result);

Print result:

result:0 

BOOL result = [first compare:second] == NSOrderedAscending;    

NSLog(@"result:%d",result);

Print result:

result:0

BOOL result = [first compare:second] == NSOrderedDecending; NSLog(@"result:%d",result);

Print result:

result:1

Compare strings regardless of case

BOOL result = [first compare:second

                     options:NSCaseInsensitiveSearch | NSNumericSearch] == NSOrderedSame;

NSLog(@"result:%d",result);

Print result:

2016-01-17 11:02:49.656 string[17889:303] 
array = (
 hello,
 world
)
2016-01-17 11:02:49.657 string[17889:303] newString = helloworld

0

5. Change string case

NSString *aString = @"A String"; 

NSString *string = @"String"; 

// A capital 

NSLog(@"aString:%@",[aString uppercaseString]);

// lowercase 

NSLog(@"string:%@",[string lowercaseString]);

// Initial case 

NSLog(@"string:%@",[string capitalizedString]);

Print result:

2016-01-17 11:02:49.656 string[17889:303] 
array = (
 hello,
 world
)
2016-01-17 11:02:49.657 string[17889:303] newString = helloworld

1

6. Search for substrings in a string

NSString *string1 = @"This is a string";

NSString *string2 = @"string";

NSRange range = [string1 rangeOfString:string2];

NSUInteger location = range.location;

NSUInteger leight = range.length;

NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%li,Leight:%li",location,leight]];

NSLog(@"astring:%@",astring);

[astring release];

Print result:

2016-01-17 11:02:49.656 string[17889:303] 
array = (
 hello,
 world
)
2016-01-17 11:02:49.657 string[17889:303] newString = helloworld

2