Question

我有两个data.table，我正在尝试将它们合并在一起。第一个列有列：code offers 第二个列有列：code offers nb_offers 我试图通过合并将第三列添加到第一个data.table。

这里提供了最小的文件：

dt1 = https://ufile.io/vjeju
dt2 = https://ufile.io/l61jc

我的问题是，对于某些行，这些值不会显示在此处。

一个工作示例：

> library(data.table)
> dt1 <- data.table(readRDS("dt1.rds"))
> dt2 <- data.table(readRDS("dt2.rds"))

> dt1[offers == "0.05"]
    code offers
1: 24428   0.05

> dt2[offers == "0.05"]
    code offers nb_offers
1: 24428   0.05         5

> merge(dt1[offers == "0.05"], dt2[offers == "0.05"], 
        by = c("code", "offers"))
    code offers nb_offers
1: 24428   0.05         5

让我们稍微改变一下：

> dt1[offers == "0.06"]
    code offers
1: 24428   0.06

> dt2[offers == "0.06"]
    code offers nb_offers
1: 24428   0.06         3

> merge(dt1[offers == "0.06"], dt2[offers == "0.06"], 
        by = c("code", "offers"))
Empty data.table (0 rows) of 3 cols: code,offers,nb_offers

这对我来说毫无意义。

我试图复制错误，但是如果我从头开始创建data.tables，那么错误就不会发生：

> tmp1 <- data.table(code = "24428", offers = 0.06)
> tmp2 <- data.table(code = "24428", offers = 0.06, nb_offers = 3)
> setkey(tmp2, code)
> merge(tmp1, tmp2, by = c("code", "offers"))
    code offers nb_offers
1: 24428   0.06         3
> all.equal(tmp1, dt1[offers == "0.06"])
[1] TRUE
> all.equal(tmp2, dt2[offers == "0.06"])
[1] TRUE

我知道我可以通过其他方式做我想做的事情，但我想了解这里发生了什么。

谢谢。

明显的“合并”导致了NA。如何调试data.tables之间的差异？

0 个答案: