Get values from NSMutablearray - ios

Question

I have a NSMutableArray that has three columns with multiple lines with float values, like this:
-0.06, -0.49, -0.76;
-1.05, -0.63, -0.77;
0.73, -0.32, -0.62;
-0.08, -0.61, -1.00;
0.15, -0.42, -0.91;
I used this lines to define the NSMutableArray (anArrayAcel):
NSString *str = [NSString stringWithFormat:#"%#, %#, %#",self.accX.text,self.accY.text, self.accZ.text];
[anArrayAcel addObject:str];
I need access this data to be used in other function. How can I access the values through specific indexes?

Answer 1

It looks like you need an array of arrays. You made an array of NSStrings instead.
Here is one way to do it:
NSMutableArray *row = [
#[
[self.accX.text floatValue]
, [self.accY.text floatValue]
, [self.accZ.text floatValue]
]
mutableCopy
];
[anArrayAcel addObject:row];
The idea is to create an array of NSMutableArrays, presumably in an event handler inside which you add rows to your array. If you do not need the nested arrays to be mutable, skip the mutableCopy part.
Now you can access your data as follows:
float x = anArrayAcel[row][0];
float y = anArrayAcel[row][1];
float z = anArrayAcel[row][2];
Note: if all rows are going to have exactly three values, x, y, and z, you may be better off creating a class to represent three floats instead of using a nested array.

Answer 2

you can design a class named Acel as below:
// Acel.h
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#interface Acel : NSObject
#property (nonatomic, assign) CGFloat accX;
#property (nonatomic, assign) CGFloat accY;
#property (nonatomic, assign) CGFloat accZ;
- (instancetype)initWithAccX:(CGFloat)accX accY:(CGFloat)accY accZ:(CGFloat)accZ;
#end
and .m is as below:
// Acel.m
#import "Acel.h"
#implementation Acel
- (instancetype)initWithAccX:(CGFloat)accX accY:(CGFloat)accY accZ:(CGFloat)accZ{
self = [super init];
if (self) {
self.accX = accX;
self.accY = accY;
self.accZ = accZ;
}
return self;
}
#end
ViewController as below:
// ViewController.h
#interface ViewController ()
#property (nonatomic, strong) NSMutableArray *acels;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.acels = [#[] mutableCopy];
Acel *acel0 = [[Acel alloc] initWithAccX:-1.1f accY:0.2f accZ:0.3f];
Acel *acel1 = [[Acel alloc] initWithAccX:-1.1444f accY:0.22f accZ:0.33f];
Acel *acel2 = [[Acel alloc] initWithAccX:-1.1411f accY:0.255f accZ:0.333f];
[_acels addObject:acel0];
[_acels addObject:acel1];
[_acels addObject:acel2];
[self accessAccel1X];
}
- (void)accessAccel1X{
Acel * acel1 = self.acels[1];
NSLog(#"%f", acel1.accX);
}
In my opinion,it is more elegant compared with two-dimensional array.
Because we don't need do like [0][1] and we avoid double circulation if you want to iterate through arrays,