For .. in traversal, enumerator, for .. in traversal Enumeration

For .. in traversal, enumerator, for .. in traversal Enumeration

# Pragma mark ------------ for looping through elements in the Set ------

// Create an array containing five string objects. Retrieve all elements in the array in reverse order and store them in another variable array.

NSArray * array = @ [@ "1", @ "2", @ "3", @ "4", @ "5"];

NSMutableArray * marray = [NSMutableArray arrayWithCapacity: 0];

For (NSInteger I = [array count]-1; I> = 0; I --){

[Marray addObject: array [I];

}

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

NSDictionary * dic =@ {@ "name": @ "zhonger", @ "sex": @ "m", @ "age": @ "29 "};

NSArray * key = [dic allKeys];

NSArray * value = [dic allValues];

For (int I = 0; I <[key count]; I ++ ){

// NSLog (@ "% @ = % @", key [I], value [I]);

// NSLog (@ "% @", [dic objectForKey: key [I]);

NSLog (@ "% @", dic [key [I]);

// How does the array access elements or objects? ObjectAtIndex:

// What is the syntactic sugar of the element accessed by the array? Array object [subscript]

// How does the dictionary access the value? Object ForKey:

// What is the syntactic sugar of the dictionary access value? Dictionary object [key]

}

// Create a group, save three pieces of information, and traverse each piece of information.

NSSet * set = [NSSet setWithObjects: @ "1", @ "888888", @ "3", nil];

NSArray * allSet = [set allObjects];

For (int I = 0; I <[allSet count]; I ++ ){

NSLog (@ "allSet is % @", allSet [I]);

}

 

# Pragma mark ------------ NSEnumerator ------

NSArray * enumArray = @ [@ "jinkangda", @ "zhubada", @ "dazi", @ "bada"];

// Create an enumerator attached to an array

NSEnumerator * rator = [enumArray objectEnumerator]; // forward

// Create an object

Id object = nil; // The capacity is empty.

While (object = [rator nextObject]) {

NSLog (@ "Forward = % @", object );

}

NSEnumerator * rator1 = [enumArray reverseObjectEnumerator];

Id object1 = nil;

While (object1 = [rator1 nextObject]) {

NSLog (@ "Reverse Order =%@", object1 );

}

// Dictionary enumeration Traversal

NSDictionary * enumDic =

@ {@ "Key1": @ {@ "key1": @ "value1 "},

@ "Key2": @ {@ "key2": @ "value2 "},

@ "Key3": @ {@ "key3": @ "value3 "}};

NSEnumerator * dicRator = [enumDic objectEnumerator];

Id value1 = nil;

While (value1 = [dicRator nextObject]) {

NSLog (@ "value1 is % @", value1 );

}

# Pragma mark ------------ for... in... quick enumeration ------

// Type * object indicates that the object type obtained from the collection is only a name. You only need to satisfy the variable naming rules.

// Collection indicates the set to be traversed.

// Operations to be performed in statements traversal, such as using enumerated objects to implement certain functions

/*

For (<# type * object #> in <# collection #> ){

<# Statements #>

}*/

For (id object in enumArray ){

NSLog (@ "----- % @", object );

}

// Use forin traversal to obtain each value in the dictionary

// Traverse the key in the dictionary and obtain the value of each key.

For (id key in enumDic ){

// NSLog (@ "% @", [enumDic objectForKey: key]);

NSLog (@ "% @", enumDic [key]);

For (id key1 in enumDic [key]) {

NSLog (@ "% @", enumDic [key] [key1]);

// NSLog (@ "% @", [[enumDic objectForKey: key] objectForKey: key1]);

}

}

// Define the delimiter array, which contains five string objects. Extract all the character strings in the array and splice the delimiter to generate a new character string.

NSArray * ar = @ [@ "I", @ "L", @ "o", @ "v", @ "eyou"];

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

For (id object in ar ){

// [Mstr stringByAppendingString: object];

[Mstr appendString: object];

}

NSLog (@ "% @", mstr );