如何理解该守则:计算范围1 (0:a) [复制]
原文：how to understand the code: to calculate the number of 1 in range(0:a) [duplicate]

我看到一部用于计算所有单位(0,a)的1比数的代码。

是否有一部关于ISO 8601的全面图书馆/单元。
原文：Is there a comprehensive library/module for ISO 8601 in ruby?

Is there already an implementation of all the date, time, duration and interval usage of the ISO 8601 standard in ruby? I mean something like a Class where you can set and get the details like, year, ...