Immutable string NSString and variable string NSMutableString, nsstring replace string

Immutable string NSString and variable string NSMutableString, nsstring replace string

Immutable string

// Create a String object

NSString * string = [[NSString alloc] initWithFormat: @ "zhong huang-"];

NSString * string1 = [[NSString alloc] initWithFormat: @ "zhonger's age is % d", 33];

NSString * string2 = [[NSString alloc] initWithFormat: @ "zhonger's gender is % @", @ "ominous"];

NSString * string3 = @ "I love iOS ";

// Obtain the length of a string

Unsigned long length = [string2 length];

// Obtain characters in the string

Unichar character = [string2 characterAtIndex: 21];

// Compare the content of two strings

BOOL isEqual = [string3 isw.tostring: string4];

// String comparison

NSComparisonResult result = [string3 compare: string4];

// Truncate the string:

// 1. substringFromIndex:

// Capture a subscript until the end.

NSString * newString = [string substringFromIndex: 5];

// 2. substringToIndex:

// Capture data from the beginning to the end of a logo

NSString * newString1 = [string substringToIndex: 5];

// 3. substringWithRange:

// Extract a few characters from the beginning and 3 from the second.

// NSMakeRange select several locations from a subscript

// NSMakeRange (<# NSUInteger loc #>, <# NSUInteger len #>)

NSString * newString2 = [string substringWithRange: NSMakeRange (2, 3)];

// Concatenate the string stringByAppendingFormat

NSString * newStr = [string stringByAppendingFormat: @ ""]; // You can also print placeholders.

NSString * newStr1 = [string stringByAppendingFormat: @ "Force % d", 2];

NSString * newStr2 = [string stringByAppendingString: @ "Force 2"];

NSString * newStr3 = [string stringByAppendingString: string1]; // The placeholder cannot be printed...

// Replace the string.

NSString * news = [string2 stringByReplacingCharactersInRange: NSMakeRange (20, 2) withString: @ "android"];

// Use this parameter when you do not know the specific position of the replace. If there are multiple replicas, replace them all.

NSString * news1 = [string2 stringByReplacingOccurrencesOfString: @ "ominous" withString: @ "female and female"];

// Convert string to int type

NSString * numberStr = @ "123 ";

Int number = [numberStr intValue];

// Uppercase and lowercase strings and uppercase letters

NSString * resultStr = [string uppercaseString];

NSString * resultStr1 = [string lowercaseString];

NSString * resultStr2 = [string capitalizedString];

// Determine whether a string starts with the specified method or how it ends.

BOOL isTrue = [string hasPrefix: @ "zh"];

BOOL isTrue1 = [string hasSuffix: @ "z"];

 

Variable string

// Create a variable string with a capacity of 0. The system will automatically apply for Space Based on the content stored in the variable string.

NSMutableString * mStr = [[NSMutableString alloc] initWithCapacity: 0];

// Set content

[MStr setString: @ "the power of the flood cannot be blocked, and the Qilin force"];

// Splicing

[MStr appendFormat: @ ", it's amazing! "];

// Delete characters in a certain range

[MStr deleteCharactersInRange: NSMakeRange (6, 2)];

// Insert a specified string starting with a subscript

[MStr insertString: @ "中 "atIndex: 2];

// Replace a string within a certain range

[MStr replaceCharactersInRange: NSMakeRange (8, 2) withString: @ "Swallow"];

NSLog (@ "mStr is % @", mStr );

Note that the use of methods is a string, so you must remember the method name. If you do not know, you can read the api documentation. The api documentation provides a detailed description of all methods.