“折叠”，是科幻中常见的概念，意指将遥远时空压缩至眼前。这正是我们想做的：将关于未来生活的种种想象，从零星的构想与孤立的产品中抽离，压缩进一条你可以漫步、互动、甚至生活的街道。
There’s a special case here: if the map contains a register at the given key, but the register contains null, the map is considered to not contain the key.
，详情可参考wps下载
Years ago, people figured out Raspberry Pi’s can accidentally double as FM radio transmitters without a need for any radio front-end (if we don’t count a single jumper wire working as an antenna). They achieved this by tying a GPIO pin to a software-controlled clock around 100 MHz to modulate audio. This created a low-powered FM radio transmitter. Due to the pin producing a square wave instead of a neat sine wave, it also emitted weaker harmonics at 300MHz, 500MHz, etc., but any basic FM radio could pick up the audio. I wondered if a similar feat could be achieved by much less powerful Raspberry Pi Pico microcontrollers.。PDF资料对此有专业解读
FT Professional