Objective-c series-NSMutableString, objective-c

Objective-c series-NSMutableString, objective-c

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NSMutableString is a subclass of NSString. In addition to the parent class method, NSMutableStirng also has some addition, deletion, modification, and replacement methods.

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Constructor

A newly added constructor:

NSMutableString * mstring = [[NSMutableString alloc] initWithCapacity: 100];

// Note:

// Define a pointer

NSMutableString * mstr;

// Mstr = @ "abc"; // mstr points to a constant, so it is immutable.

Mstr = [[NSString alloc] init]; // This is the open-up immutable string space and immutable string space.

Mstr = [[NSMutableStirng alloc] init]; // This can be changed.

Likewise:

NSString str = [[NSMutableString alloc] init]; // str is also a variable string!

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// Add

NSMutableString * mstr = [[NSMutableString alloc] init];

// Append a format string to the end of the string mstr

[Mstr appendFormat: @ "[a = % I]-[c = % c]-[s = % s]", 123, 'x', "cstring"];

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

NSLog (@ "mstr length: % lu", [mstr length]);

// Append an oc string to the end of the string mstr, corresponding to strcat in c

[Mstr appendString: @ "-[appendString]"];

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

NSLog (@ "mstr length: % lu", [mstr length]);

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// Delete

NSMutableString * mstr = [[NSMutableString alloc] initWithString: @ "123abc123abc"];

NSLog (@ "before delete, mstr: % @, mstr length: % lu", mstr, [mstr length]);

// Delete a specified range

[Mstr deleteCharactersInRange: NSMakeRange (9, 3)];

NSLog (@ "after delete, mstr: % @, the length of mstr is: % lu", mstr, [mstr length]);

// Search for a range and delete it based on the range.

// Mstr content: 123abc123

// Locate the abc range in mstr. A struct {3} should be returned}

// Pass this struct to deleteCharactersInRange: Method to delete abc.

[Mstr deleteCharactersInRange: [mstr rangeOfString: @ "abc"];

NSLog (@ "after the second abc deletion, mstr: % @, mstr length: % lu", mstr, [mstr length]);

// Question 1: How to delete substrings that appear multiple times in a string?

// Question 2: How do I replace the substrings that appear multiple times in a string?

// 1. Process cyclically

[Mstr appendString: @ "abc123abc123abc123"];

NSLog (@ "append an abc123. .. After mstr: % @, mstr length: % lu", mstr, [mstr length]);

// There are three abc substrings in mstr

Printf ("NSNotFound = % lu \ n", NSNotFound );

While (1 ){

Nsange range = [mstr rangeOfString: @ "abc"];

If (range. location = NSNotFound ){

Break;

}

[Mstr deleteCharactersInRange: range];

// [Mstr replaceCharactersInRange: [mstr rangeOfString: @ "123"] withString: @ "woca"];

}

NSLog (@ "after abc is deleted in the loop, mstr :%@, the length of mstr is: % lu", mstr, [mstr length]);

// Replace a character in a certain range in the original string with a new string

[Mstr replaceCharactersInRange: NSMakeRange (2, 1) withString: @ "[replace]"];

NSLog (@ "after the replacement method is called, mstr: % @, the length of mstr is: % lu", mstr, [mstr length]);

 

// Insert a string at a subscript

[Mstr insertString: @ "[insertString]" atIndex: 1];

NSLog (@ "after the insertion method is called, mstr: % @, the length of mstr is: % lu", mstr, [mstr length]);

// Set the string

[Mstr setString: @ "[this is setString]"];

NSLog (@ "after the setString method is called, mstr: % @, the length of mstr is: % lu", mstr, [mstr length]);

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