Question

我在php中创建切换功能，我想知道是否有可能做出这样的情况之一：

+ (UIFont *)addFallbacktoFont:(UIFont*)font{
   UIFontDescriptor* originalDescriptor = [font fontDescriptor];

   UIFontDescriptor* fallbackDescriptor = [originalDescriptor fontDescriptorByAddingAttributes:@{UIFontDescriptorNameAttribute:@"Helvetica Neue"}];

   UIFontDescriptor* repaired = [originalDescriptor fontDescriptorByAddingAttributes:@{UIFontDescriptorCascadeListAttribute:@[
                                                                                            fallbackDescriptor
                                                                                            ]}];

   font = [UIFont fontWithDescriptor:repaired size:0.0];

   return font;
}

我想执行最后一种情况，例如$ message：“project start”或“start project”。我认为这是因为preg_match返回0或1.有没有办法使这段代码有效？

Answer 1

如果您希望保存代码的可读性和编译器友好性，请使用此选项：

switch($message){
        case 'hi':
            $output = $jsonWelcome;
            break;
        default:
            $output = preg_match('/start/', $message) ? $jsonHelp : "";
}

Answer 2

您可以使用此代码段：

switch(true){
        case $message == 'hi':
            $output = $jsonWelcome;
            break;
        case 1 == preg_match('/start/', $message):
            $output = $jsonHelp;
            break;
}

所有条件都应评估true

Answer 3

let always = (() => {
  let worker = (f, done) => {
    return Promise.resolve(f()).then(done, done);
  };
  return function always(f) {
    return [
      result => worker(f, () => result),
      error  => worker(f, () => { throw error; })
    ];
  }
})();

test("p1", 500, false, "good").then(...always(
  () => {
    test("p2", 500, true, "bad");
  }
));

function test(name, delay, fail, value) {
  // Make our test promise
  let p = new Promise((resolve, reject) => {
    console.log(name, `created with ${delay}ms delay before settling`);
    setTimeout(() => {
      if (fail) {
        console.log(name, "rejecting");
        reject(value);
      } else {
        console.log(name, "resolving");
        resolve(value);
      }
    }, delay);
  });

  // Use it
  return p.then(
    result => {
      console.log(name, "initial resolution:", result);
      return result;
    },
    error => {
      console.log(name, "initial rejection; propagating it");
      throw error;
    }
  )
  .then(...always(() => {
    console.log(name, "in finally");
  }))
  .then(
    result => {
      console.log(name, "resolved:", result);
    },
    error => {
      console.log(name, "rejected:", error);
    }
  );
}

应该可以正常工作。

工作代码示例： http://sandbox.onlinephpfunctions.com/code/99ab518718ce9488277619a33dbfdf353f0c2316

PHP中的切换案例中的Preg_match？

3 个答案: