如何在 R 中使用 fuzzyjoin::difference_* 执行模糊连接

Question

我正在处理两个不同的数据集，我想根据阈值将它们合并。假设这两个数据帧如下所示：

library(dplyr)
library(fuzzyjoin)
library(lubridate)

df1 = data_frame(Item=1:5, 
                 DateTime=c("2015-01-01 11:12:14", "2015-01-02 09:15:23", 
                            "2015-01-02 15:46:11", "2015-04-19 22:11:33", 
                            "2015-06-10 07:00:00"), 
                 Count=c(1, 6, 11, 15, 9), 
                 Name="Sterling", 
                 Friend=c("Pam", "Cyril", "Cheryl", "Mallory", "Lana"))
df1$DateTime = ymd_hms(df1$DateTime)

df2 = data_frame(Item=21:25, 
                 DateTime=c("2015-01-01 11:12:15", "2015-01-02 19:15:23", 
                            "2015-01-02 15:46:11", "2015-05-19 22:11:33", 
                            "2015-06-10 07:00:02"), 
                 Count=c(3, 7, 11, 15, 8), 
                 Name="Sterling", 
                 Friend=c("Pam", "Kreger", "Woodhouse", "Gillete", "Lana"))
df2$DateTime = ymd_hms(df2$DateTime)

我现在想要的是能够在两秒内根据 DateTime 和 Count 的模糊匹配左连接 df2 和 df1它们各自的值，而除 Item 之外的所有其他值都是相同的。我以为我可以通过以下方式到达那里：

df1 %>%
  difference_left_join(df2, by=c("DateTime", "Count"), max_dist=2)

但这给了我以下输出：

 # A tibble: 8 × 10
  Item.x          DateTime.x Count.x   Name.x Friend.x Item.y          DateTime.y Count.y   Name.y  Friend.y
   <int>              <dttm>   <dbl>    <chr>    <chr>  <int>              <dttm>   <dbl>    <chr>     <chr>
1      1 2015-01-01 11:12:14       1 Sterling      Pam     21 2015-01-01 11:12:15       3 Sterling       Pam
2      1 2015-01-01 11:12:14       1 Sterling      Pam     21 2015-01-01 11:12:15       3 Sterling       Pam
3      2 2015-01-02 09:15:23       6 Sterling    Cyril     NA                <NA>      NA     <NA>      <NA>
4      3 2015-01-02 15:46:11      11 Sterling   Cheryl     23 2015-01-02 15:46:11      11 Sterling Woodhouse
5      3 2015-01-02 15:46:11      11 Sterling   Cheryl     23 2015-01-02 15:46:11      11 Sterling Woodhouse
6      4 2015-04-19 22:11:33      15 Sterling  Mallory     NA                <NA>      NA     <NA>      <NA>
7      5 2015-06-10 07:00:00       9 Sterling     Lana     25 2015-06-10 07:00:02       8 Sterling      Lana
8      5 2015-06-10 07:00:00       9 Sterling     Lana     25 2015-06-10 07:00:02       8 Sterling      Lana

这很接近，除了第 3 行不应该合并，因为名称不同（我希望第 2 行在给定阈值的情况下合并，即使我不希望它合并）。

如何得到以下数据框？请注意，尽管 DateTime 和 Count 满足阈值限制，但 df2 的第二行和第三行未合并。这是因为其他列（Item 除外）不相同。

desired_output
#   Item            DateTime Count     Name  Friend
# 1    3 2015-01-02 15:46:11    11 Sterling  Cheryl
# 2    2 2015-01-02 09:15:23     6 Sterling   Cyril
# 3    5 2015-06-10 07:00:00     9 Sterling    Lana
# 4   25 2015-06-10 07:00:02     8 Sterling    Lana
# 5    4 2015-04-19 22:11:33    15 Sterling Mallory
# 6    1 2015-01-01 11:12:14     1 Sterling     Pam
# 7   21 2015-01-01 11:12:15     3 Sterling     Pam

Answer 1

好的，所以，您收到的消息是因为无法在非数字列上计算模糊匹配。

要做的事情就是把它转换成数字。由于您的卡尺以秒为单位，我将其转换为秒，然后将它们设为数字：

library(dplyr)
library(fuzzyjoin)
library(lubridate)

df1 = data_frame(Item=1:5, 
                 DateTime=c("2015-01-01 11:12:14", "2015-01-02 09:15:23", 
                            "2015-01-02 15:46:11", "2015-04-19 22:11:33", 
                            "2015-06-10 07:00:00"), 
                 Count=c(1, 6, 11, 15, 9), 
                 Name="Sterling", 
                 Friend=c("Pam", "Cyril", "Cheryl", "Mallory", "Lana"))
df1$DateTime1 = as.numeric(seconds(ymd_hms(df1$DateTime)))

df2 = data_frame(Item=21:25, 
                 DateTime=c("2015-01-01 11:12:15", "2015-01-02 19:25:56", 
                            "2015-01-02 15:46:11", "2015-05-19 22:11:33", 
                            "2015-06-10 07:00:02"), 
                 Count=c(3, 6, 11, 15, 8), 
                 Name="Sterling", 
                 Friend=c("Pam", "Kreger", "Woodhouse", "Gillete", "Lana"))
df2$DateTime1 = as.numeric(seconds(ymd_hms(df2$DateTime)))

df1 %>%
  difference_left_join(y=df2, by=c("DateTime1", "Count"), max_dist=2)

根据我们在评论中的讨论，将其子集化为其他字符列匹配的情况的简单调整是：

df1[df2$Friend == df1$Friend,] %>%
  difference_left_join(y=df2[df2$Friend == df1$Friend,], by=c("DateTime1", "Count"), max_dist=2)

该示例仅适用于 Friend，但您当然可以使用 & 来处理多个列。

如何在 R 中使用 fuzzyjoin::difference_* 执行模糊连接

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