如何从日期中获取周数? [英] How to get week numbers from dates?

问题描述

在 R 中寻找将日期转换为周数(年份)的函数，我从包 data.table 中查找了 week.但是，我观察到了一些奇怪的行为:

Looking for a function in R to convert dates into week numbers (of year) I went for week from package data.table. However, I observed some strange behaviour:

> week("2014-03-16") # Sun, expecting 11
[1] 11
> week("2014-03-17") # Mon, expecting 12
[1] 11
> week("2014-03-18") # Tue, expecting 12
[1] 12

为什么星期二改为 12，而不是星期一?我错过了什么?(时区应该无关紧要，因为只有日期?！)

Why is the week number switching to 12 on tuesday, instead of monday? What am I missing? (Timezone should be irrelevant as there are just dates?!)

对(基础)R 函数的其他建议也表示赞赏.

Other suggestions for (base) R functions are appreciated as well.

推荐答案

Base package

使用函数 strftime 传递参数 %V 以 ISO 8601 中定义的十进制数 (01–53) 形式获取一年中的第几周.(文档中的更多详细信息:?strftime)

Base package

Using the function strftime passing the argument %V to obtain the week of the year as decimal number (01–53) as defined in ISO 8601. (More details in the documentarion: ?strftime)

strftime(c("2014-03-16", "2014-03-17","2014-03-18", "2014-01-01"), format = "%V")

输出:

[1] "11" "12" "12" "01"

这篇关于如何从日期中获取周数?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！