1.使用valueForKeyPath求數(shù)組和、最大值、最小值及平均值

NSMutableArray* array = [NSMutableArray array];
for (int i = 0; i < 10; i++) {
  CGFloat num = arc4random() % 100 + 1;
  [array addObject:[NSNumber numberWithFloat:num]];
}  
CGFloat sumValue = [[array valueForKeyPath:@"@sum.floatValue"] floatValue];
CGFloat maxValue = [[array valueForKeyPath:@"@max.floatValue"] floatValue];
CGFloat minValue = [[array valueForKeyPath:@"@min.floatValue"] floatValue];
CGFloat avgValue = [[array valueForKeyPath:@"@avg.floatValue"] floatValue];

2.獲取漢字對應(yīng)的拼音

 + (NSString *)getPinyinFormChinese:(NSString *)chinese {
    // 將NSString裝換成NSMutableString
    NSMutableString *pinyin = [chinese mutableCopy];
    // 將漢字轉(zhuǎn)換為拼音(帶音標(biāo))
    CFStringTransform((__bridge CFMutableStringRef)pinyin, NULL, kCFStringTransformMandarinLatin, NO);
    // 去掉拼音的音標(biāo)(不帶音標(biāo))
    CFStringTransform((__bridge CFMutableStringRef)pinyin, NULL, kCFStringTransformStripCombiningMarks, NO);
    return pinyin;
}

3.代碼執(zhí)行效率檢測

CFAbsoluteTime start = CFAbsoluteTimeGetCurrent();
 {測試代碼}
CFAbsoluteTime end = CFAbsoluteTimeGetCurrent();
NSLog(@"代碼執(zhí)行時(shí)間: %0.3f", end - start);

4.生成隨機(jī)字符串

NSInteger length = 10;    
char data[length];   
for (int i = 0; i < length; i++) {       
    data[i] = 'A' + (arc4random_uniform(26));    
}
NSString *string = [[NSString alloc] initWithBytes:data length:length encoding:NSUTF8StringEncoding];

5.設(shè)置應(yīng)用可以通過iTunes與電腦傳輸文件

在Info.plist中添加Application supports iTunes file sharing字段 Value設(shè)置為YES

6.Xcode文件路徑

項(xiàng)目描述文件路徑： ~/Library/MobileDevice/Provisioning Profiles
打包項(xiàng)目路徑（Archive）：~/Library/Developer/Xcode/Products

7.UIView轉(zhuǎn)換為UIImage

// 將UIView轉(zhuǎn)換為UIImage
- (UIImage *)convertViewToImage:(UIView *)view {
    CGSize size = view.bounds.size;
   // 下面方法，第一個(gè)參數(shù)表示區(qū)域大小。第二個(gè)參數(shù)表示是否是非透明的。如果需要顯示半透明效果，需要傳NO，否則傳YES。第三個(gè)參數(shù)就是屏幕密度了
    UIGraphicsBeginImageContextWithOptions(size, NO, [UIScreen mainScreen].scale);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}