对象:system.file 说明:提供一系列针对文件操作的方法. 注意:参数中的filePath 均为相对网站根目录路径 目录: 方法 返回 说明 system.file.exists(filePath) [True | False]  检测文件是否存在 system.file.name(filePath) [String]  获取文件名(包含扩展名) system.file.extend(filePath) [String]  获取文件扩展名 system.file.baseName(fil

数学方法: Saying that a number contains 1000 digits is the same as saying that it's greater than 10**999. The nth Fibonacci number is [phi**n / sqrt(5)], where the brackets denote "nearest integer". So we need phi**n/sqrt(5) > 10**999 n * log(phi

https://www.quora.com/What-is-the-best-way-to-download-YouTube-videos-for-free There are various methods to download YouTube video for free. How To Download Youtube Videos Without any software Open YouTube from your mobile browser and open the video