Python的yield似乎不適合用在recursive function裡面

這幾天發現Python 的 yield用在recursive function裡面，執行的方式跟想像中的，差別很大，但是拿掉yield的話，recursive function call執行的方式又正常，真是神奇啊。

設定電腦攝影機和麥克風在Chrome的存取權限 (轉貼)

Use your camera & microphone

You can use your camera and microphone for sites in Chrome, like Google Hangouts or Skype.

1. Open Chrome .
2. Go to a site that wants to use your microphone and camera.
3. When prompted, choose Allow or Block.

The permission you choose changes what sites can do with your camera and mic:

• Allowed sites: 
  • Sites can start to record when you're on the site. If you're in a different Chrome tab or a different app, a site can't start recording.
  • If you lock your phone screen, the site will stop using your camera. It can still use your mic.
• Blocked sites: Some sites won't work if you block them. For example, you won't be able to join a video conference.

Change a site's camera and microphone permissions

1. Open Chrome .
2. At the top right, click More   Settings.
3. At the bottom, click Advanced.
4. Under "Privacy and security," click Content settings.
5. Click Camera or Microphone.
6. Turn Ask before accessing on or off.

To remove an existing exception or permission, to the left of the site, click Delete .

If you're using a Chrome device at work or school, your network administrator can set camera and microphone settings for you. In that case, you can't change them here. Learn about using a managed Chrome device.

Change Adobe Flash camera and microphone access

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Fix problems with your mic

If your microphone isn’t working, try these steps:

Step 1: Make sure you aren't muted

If you’re using a headset, make sure the mute switch on the cord is off. Also, make sure you aren't muted on the website (like Google Hangouts or Skype).

Step 2: Check your system settings

If you're on a computer, make sure your microphone is the default recording device, and that recording levels are correct:

• Windows
• Mac

Step 3: Contact your manufacturer

If you’re still having problems, contact your microphone’s manufacturer.