根据一个数值寻找数组中最接近这个数值的对象

- (NSInteger)getMinValueShowLevel:(NSArray *)showLevels mapZoomLevel:(CGFloat)mapZoomLevel{
    NSInteger suitValue = (int)mapZoomLevel
    NSInteger diffLevel = 9999
    for (NSNumber *showLevel in showLevels) {
        NSInteger diffLevelTmp = fabs(mapZoomLevel - [showLevel intValue])
        if (diffLevelTmp < diffLevel) {
            diffLevel = diffLevelTmp;
            suitValue = [showLevel intValue]
        }
    }
    return suitValue
}
注:代码中
showLevels:存有数值对象,如: showLevels = @[@(12), @(7), @(9)]
suitValue:找到的最合适的值
diffLevel:层级差
mapZoomLevel:参照层级,根据这个层级,找到数组中最接近这个数的值