R-使用开始和结束日期计算一段时间内的项目计数 [英] R- Calculate a count of items over time using start and end dates

问题描述

我想使用开始和结束日期计算一段时间内的项目数量。

I want to calculate a count of items over time using their Start and End dates.

某些示例数据

START <- as.Date(c("2014-01-01", "2014-01-02","2014-01-03","2014-01-03"))
END <- as.Date(c("2014-01-04", "2014-01-03","2014-01-03","2014-01-04"))
df <- data.frame(START,END)
df

给

       START        END
1 2014-01-01 2014-01-04
2 2014-01-02 2014-01-03
3 2014-01-03 2014-01-03
4 2014-01-03 2014-01-04

表显示这些项目的时间（根据其开始和结束时间）的计数如下所示：

A table showing a count of these items across time (based on their Start and End times) is as follows:

DATETIME    COUNT
2014-01-01   1 
2014-01-02   2 
2014-01-03   4 
2014-01-04   2 

可以使用R来完成，特别是使用dplyr？非常感谢。

Can this be done using R, especially using dplyr? Many thanks.

推荐答案

这样做。您可以根据需要更改列名。

This would do it. You can change the column names as necessary.

as.data.frame(table(Reduce(c, Map(seq, df$START, df$END, by = 1))))
#         Var1 Freq
# 1 2014-01-01    1
# 2 2014-01-02    2
# 3 2014-01-03    4
# 4 2014-01-04    2

如前所述在评论中，上述解决方案中的 Var1 现在是一个因素，而不是日期。要将日期类保留在第一列中，您可以对上述解决方案进行更多工作，或者使用 plyr :: count 而不是作为。 data.frame（table（...））

As noted in the comments, Var1 in the above solution is now a factor, and not a date. To keep the date class in the first column, you could do some more work to the above solution, or use plyr::count instead of as.data.frame(table(...))

library(plyr)
count(Reduce(c, Map(seq, df$START, df$END, by = 1)))
#            x freq
# 1 2014-01-01    1
# 2 2014-01-02    2
# 3 2014-01-03    4
# 4 2014-01-04    2

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