按日期范围加入表 [英] Join tables by date range

问题描述

我正在寻找按日期范围加入两个表的简单方法。 1表包含确切日期，另一个表包含两个变量，用于标识时间段的开始和结束。如果第一张表中的日期与第二个表格的范围相符，我需要加入表格。

I am looking for simple method to join two tables by date range. 1 table contains exact date, another table contains two variables identifying beginning and ending of the time period. I need to join tables if date in first table is withing range from second table.

data1 <- data.table(date = c('2010-01-21', '2010-01-25', '2010-02-02', '2010-02-09'),
                name = c('id1','id2','id3','id4'))


data2 <- data.table(beginning=c('2010-01-15', '2010-01-23', '2010-01-30', '2010-02-05'), 
                ending = c('2010-01-22','2010-01-29','2010-02-04','2010-02-13'),
                class = c(1,2,3,4))

result <- data.table(date = c('2010-01-21', '2010-01-25', '2010-02-02', '2010-02-09'),
                 beginning=c('2010-01-15', '2010-01-23', '2010-01-30', '2010-02-05'), 
                 ending = c('2010-01-22','2010-01-29','2010-02-04','2010-02-13'),
                 name = c('id1','id2','id3','id4'),
                 class = c(1,2,3,4))

有任何帮助吗？我发现几个难点的例子，但由于格式，他们甚至没有处理我的数据。我需要这样的东西：

Any help please? I found few difficult examples but they don't even work on my data because of formats. I need something like:

select * from data1
left join
select * from data2
where data2.beginning <= data1.date <= data2.ending

谢谢

推荐答案

我知道以下看起来可怕的基数，但这是我想出来的。最好使用'sqldf'包（见下文）。

I know the following looks horrible in base, but here's what I came up with. It's better to use the 'sqldf' package (see below).

library(data.table)
data1 <- data.table(date = c('2010-01-21', '2010-01-25', '2010-02-02', '2010-02-09'),
                    name = c('id1','id2','id3','id4'))


data2 <- data.table(beginning=c('2010-01-15', '2010-01-23', '2010-01-30', '2010-02-05'), 
                    ending = c('2010-01-22','2010-01-29','2010-02-04','2010-02-13'),
                    class = c(1,2,3,4))

result <- cbind(data1,"beginning"=sapply(1:nrow(data2),function(x) data2$beginning[data2$beginning[x]<data1$date & data2$ending[x]>data1$date]),
            "ending"=sapply(1:nrow(data2),function(x) data2$ending[data2$beginning[x]<data1$date & data2$ending[x]>data1$date]),
            "class"=sapply(1:nrow(data2),function(x) data2$class[data2$beginning[x]<data1$date & data2$ending[x]>data1$date]))

使用包sqldf：

library(sqldf)
result = sqldf("select * from data1
                left join data2
                on data1.date between data2.beginning and data2.ending")

这篇关于按日期范围加入表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！