Objective-c two-dimensional array of __ two-dimensional arrays

In the actual project development, two-dimensional arrays are often used in the data structure. The two-dimensional array in OC is also created by a one-dimensional array, and today we'll explain how to use a two-dimensional array in OC.

"Initialize two-dimensional arrays with Nsarray"

Both one-dimensional and two-dimensional arrays initialized with Nsarray are variable groups.

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[]) {
  @autoreleasepool {
    
    
    // Defines 2 one-dimensional arrays;
    nsarray *firstrow = [[Nsarray alloc] initwithobjects:@ "1", @ "2", @ "3", nil];
    Nsarray *secondrow = [[Nsarray alloc] initwithobjects:@ "4", @ "5", @ "6", nil];
    
    Use one-dimensional arrays to initialize two-dimensional arrays;
    nsarray *my2darray = [[Nsarray alloc] initwithobjects:firstrow,secondrow, nil];
    Output two-dimensional array object;
    NSLog (@ "Two-dimensional array:%@", My2darray);
    
    Traversal of two-dimensional arrays; for
    (int i = 0; i < [My2darray count]; i++) {for
      (int j = 0; J < Firstrow.count; J +) {
        NS Log (@ "Two-dimensional array element:%@", [[My2darray objectatindex:i] objectatindex:j]);
  }} return 0;
}

Print the results as follows:

。

"Initialize two-dimensional arrays with Nsmutablearray"

Both one-dimensional and two-dimensional arrays initialized with Nsmutablearray are mutable and can be modified and inserted;

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[]) {
  @autoreleasepool {
    
    Nsmutablearray *firstrow = [[Nsmutablearray alloc] initwithobjects:@ "One", @ "," @ "," nil];
    Nsmutablearray *secondrow = [[Nsmutablearray alloc] initwithobjects:@ "the", @ "", @ "a", nil];
    Nsmutablearray *my2darray = [[Nsmutablearray alloc] initwithobjects:firstrow,secondrow, nil];
    
Insert a data
    [[My2darray objectatindex:0] insertobject:@ "IOS" atindex:3];
    NSLog (@ "%@", My2darray);
    
    [[My2darray objectatindex:1] insertobject:@ "OC" atindex:0];
    NSLog (@ "%@", My2darray);
    
    
  }
  return 0;
}

Print the results as follows:

。

"Fast traversal of two-dimensional arrays with for-in"

#import <Foundation/Foundation.h> int main (int argc, const char * argv[]) {@autoreleasepool {//definition
    2 one-dimensional array; nsarray *firstrow = [[Nsarray alloc] initwithobjects:@ "1", @ "2", @ "3", nil];
    
    Nsarray *secondrow = [[Nsarray alloc] initwithobjects:@ "4", @ "5", @ "6", nil];
    
    Use one-dimensional arrays to initialize two-dimensional arrays; Nsarray *my2darray = [[Nsarray alloc] initwithobjects:firstrow,secondrow, nil];
        Traversal of two-dimensional arrays; for (int i = 0; i < [My2darray count]; i++) {for (int j = 0; J < Firstrow.count; J +) {
      NSLog (@ "Two-dimensional array element:%@", [[[My2darray objectatindex:i] objectatindex:j]);
    
    }//Print one-dimensional array of a dimension NSLog (@ "one-dimensional array:%@", [My2darray objectatindex:0]);
    Use for-in to quickly traverse a one-dimensional array in a two-dimensional array for (Nsarray *arr in My2darray) {NSLog (a one-dimensional array in a two-dimensional array:%@, arr);
        ///Use for-in to quickly traverse each element of a two-dimensional array for (Nsarray *arr in My2darray) {for (NSString *str in arr) {
      NSLog (@ "for-in results:%@", str);
}} return 0; }

Print results:

。

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