Summary of common operation methods of the string NSString in ES0en ES1en

1. Create a string

(1) Constant string

NSString *string = @"i am an iOSDevTip!";

(2) Common creation methods

NSString *string = [[NSString alloc] init];
string = @"i am an iOSDevTip too!";

(3) Use initWithString to create strings

NSString *string = [[NSString alloc] initWithString:@"iOSDevTip is here!"];

2. Format the create string

(1) int format string

int age = 20;

NSString *personAge = [NSString stringWithFormat:@"this person age is %d",age];

Since int formats strings, float, double, and so on can also format strings.

(2) NSString format string

NSString *name = @"iOSDevTip";

NSString *personName = [NSString stringWithFormat:@"this person name is %@",name];

3. String comparison

(1) Comparison of isEqualToString methods

NSString *stingOne = @"This is an iOSDevTip!";

NSString *stringTwo = @"This is an iOSDevTip!";

BOOL result = [stingOne isEqualToString:stringTwo];

(2) Comparison of compare methods

BOOL result = [stingOne compare:stringTwo] == NSOrderedSame;

compare: The method returns a value of type NSComparisonResult. NSComparisonResult has the following enumerated values.

typedef NS_ENUM(NSInteger, NSComparisonResult) {NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending};

4. String capitalization conversion

(1) Lowercase to uppercase

 NSString *string = @"This is an iOSDevTip!";

[string lowercaseString];

(2) Uppercase to lowercase

NSString *string = @"This is an iOSDevTip!";

[string uppercaseString];

(3) Capital letters

NSString *string = @"ligang";

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

Print:

2015-07-16 23:06:11.652 iOSStrongDemo[10279:3062010] string: Ligang

5. Intercept the string

(1) substringToIndex intercepts the string

NSString *string = @"This is a operation string!";

NSString *subToString = [string substringToIndex:6];

(2) The intercepted subToString is This i

substringFromIndex intercepts the string

NSString *subFromString = [string substringFromIndex:6];

(3) The intercepted subFromString is s a operation string!

substringWithRange intercepts the string

NSString *rangeString = [string substringWithRange:NSMakeRange(6, 3)];

s a!

6. Determine if the string contains another string

(1) rangeOfString judgment

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

NSString *string2 = @"iOSDevTip";

NSRange range = [string1 rangeOfString:string2];

NSInteger location = range.location;

NSInteger leight = range.length;

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

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

Print it out:

iOSStrongDemo[8837:2221170] logString:Location:10,Leight:9

(2) Judge whether the presuffix is included

NSString *string = @"I love China";

BOOL isHasI = [string hasPrefix:@"I"];

BOOL isHasChina = [string hasSuffix:@"China"];

7. Split strings

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

NSArray *array = [string componentsSeparatedByString:@"a"];

NSString *string1 = [array objectAtIndex:0];

NSString *string2 = [array objectAtIndex:1];

NSLog(@"string1:%@  string2:%@",string1,string2);

Print:

2015-07-16 22:40:39.559 iOSStrongDemo[10165:3055448] string1:This is  string2: iOSDevTip

8. Insert string

NSMutableString *string = [[NSMutableString alloc] initWithString:@"I China"];

[string insertString:@"Love " atIndex:2];

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

Print:
2015-07-16 22:44:10.706 iOSStrongDemo[10206:3057014] string: I Love China
(1) Append a string

NSString *string = [[NSString alloc] init];
string = @"i am an iOSDevTip too!";

8
Print:

2015-07-16 22:42:32.305 iOSStrongDemo[10189:3056410] string:I Love China

9. Delete strings

NSString *string = [[NSString alloc] init];
string = @"i am an iOSDevTip too!";

9
Print:

2015-07-16 22:46:58.437 iOSStrongDemo[10219:3057749] String1: I China

Replace the string

NSString *string = [[NSString alloc] initWithString:@"iOSDevTip is here!"];

0
Print:

2015-07-16 22:56:07.405 iOSStrongDemo[10236:3059503] replaceString: I like China

11. Removes Spaces and newlines at the beginning and end of the string

NSString *string = @" I love China ";

NSString *text = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

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

Print:

2015-07-16 23:00:47.845 iOSStrongDemo[10265:3061013] text:I love China