Question

这里有下标错误，但我不确定原因。这次我确保匹配的类型，但现在我收到错误，因为他们匹配。

不能使用“Double”类型的索引下标“[Double]”类型的值

let maxPeriod:Double = 1.5  
let minPeriod:Double = 0.1 
let invalidEntry:Float = -100
let maxPeriodsToStore:Double = 20
let averageSize:Int = 20


class Detector {

    let session = AVCaptureSession()
    var camera : AVCaptureDevice?

    var upVals: [Float] = [] 
    var downVals: [Float] = [] 
    var upValIndex: Int?
    var downValIndex: Int?

    var lastVal: Float?
    var periodStart: Float?
    var periods: [Double] = []
    var periodTimes: [Double] = []

    var periodIndex: Int?
    var started: Bool?
    var freq: Float?
    var average: Float?

    var wasDown: Bool?


    func reset() {


        for var i:Double = 0; i < maxPeriodsToStore; i++ {
            periods[i] = invalidEntry // error: Cannot subscript a value of type '[Double]' with an index of type 'Double'
        }
        for var i:Int = 0; i < averageSize; i++ {
            upVals[i] = invalidEntry
            downVals[i] = invalidEntry
        }
        freq = 0.5
        periodIndex = 0
        downValIndex = 0
        upValIndex = 0
    }

原始Objective-C代码

// Detector.m

#import <QuartzCore/QuartzCore.h>
#import "Detector.h"
#import <vector>
#import <algorithm>

#define MAX_PERIOD 1.5
#define MIN_PERIOD 0.1
#define INVALID_ENTRY -100

@implementation Detector

@synthesize periodStart;


- (id) init
{
self = [super init];
if (self != nil) {
// set everything to invalid
[self reset];
}
return self;
}

-(void) reset {
for(int i=0; i<MAX_PERIODS_TO_STORE; i++) {
    periods[i]=INVALID_ENTRY;
}
for(int i=0; i<AVERAGE_SIZE; i++) {
    upVals[i]=INVALID_ENTRY;
    downVals[i]=INVALID_ENTRY;
}   
  freq=0.5;
  periodIndex=0;
  downValIndex=0;
  upValIndex=0;
}


// Detector.h


#import <Foundation/Foundation.h>

#define MAX_PERIODS_TO_STORE 20
#define AVERAGE_SIZE 20
#define INVALID_PERIOD -1

@interface Detector : NSObject {  
float upVals[AVERAGE_SIZE];
float downVals[AVERAGE_SIZE];
int upValIndex;
int downValIndex;

float lastVal;
float periodStart;
double periods[MAX_PERIODS_TO_STORE];
double periodTimes[MAX_PERIODS_TO_STORE];

int periodIndex;
bool started;
float freq;
float average;

bool wasDown;
}

@property (nonatomic, assign) float periodStart; 


-(float) addNewValue:(float) newVal atTime:(double) time; 
-(float) getAverage; 
-(void) reset; 
@end

Answer 1

如果您要将大量代码粘贴到您的问题中，您应该清楚地指出哪条线路出错。

我确实看了你的代码并发现了问题。您不应该使用带有Double的for循环来索引数组。而是改变你的for循环以使用Int变量，然后如果你需要用其他双精度数学进行数学运算，则将其强制转换为Double。

不能使用“Double”类型的索引下标“Double”类型的值

1 个答案: