我对R数据帧中缺少等效的数组弹出感到困惑。我检查了dplyr，没有什么比它更合适了。
这里是数据框1，它只不过是单词，数字和组合词。目标是按顺序将问题从数据帧2匹配到数据帧1的内容，当不再有匹配项时停止。
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</html>dplyr的left_join似乎是合乎逻辑的选择，但它不起作用，而是吐出一些看起来更像是完全联接的东西。
DF1
Word Volume Group
tuna 100 fish
tuna fish 90 fish
chicken eggs 90 eggs
ostrich eggs 80 eggs
DF2
Group_Word Question
fish how big is a tuna fish?
fish what's the best tasting tuna fish?
eggs how many eggs does a chicken lay per day?
eggs how to poach eggs?
eggs do eggs need to be refrigerated?
beef what's the best flavor of beef
这是预期/预期结果：
blendeddf <- left_join(DF1,DF2, by =c("Group" = "Group_Word"))
这是实际结果：
DF1
Word Volume Group
tuna 100 fish how big is a tuna fish?
tuna fish 90 fish what's the best tasting tuna fish?
chicken eggs 90 eggs how many eggs does a chicken lay per day?
ostrich eggs 80 eggs how to poach eggs?
如果我在PHP中执行此操作，则先是array_match，然后是array_pop才能删除项目（以避免重复），但是我不知道如何在R中完成此操作。
已发送代码：
Word Volume Group Question
1 tuna 100 fish how big is a tuna fish?
2 tuna 100 fish what's the best tasting tuna fish?
3 tuna fish 90 fish how big is a tuna fish?
4 tuna fish 90 fish what's the best tasting tuna fish?
5 chicken eggs 90 eggs how many eggs does a chicken lay per day?
6 chicken eggs 90 eggs how to poach eggs?
7 chicken eggs 90 eggs do eggs need to be refrigerated?
8 ostrich eggs 80 eggs how many eggs does a chicken lay per day?
9 ostrich eggs 80 eggs how to poach eggs?
10 ostrich eggs 80 eggs do eggs need to be refrigerated?
答案 0 :(得分：2)
您可以通过在每个组中添加一个额外的列来标记数字来获得预期的结果：
DF1 = DF1 %>%
group_by(Group) %>%
mutate(GroupNum = 1:n())
DF2 = DF2 %>%
group_by(Group_Word) %>%
mutate(GroupNum = 1:n())
DF1 %>%
left_join(DF2, by = c("Group" = "Group_Word", "GroupNum"))
输出：
# A tibble: 4 x 5
# Groups: Group [2]
Word Volume Group GroupNum Question
<chr> <int> <chr> <int> <chr>
1 tuna 100 fish 1 how big is a tuna fish?
2 tuna fish 90 fish 2 what's the best tasting tuna fish?
3 chicken eggs 90 eggs 1 how many eggs does a chicken lay per day?
4 ostrich eggs 80 eggs 2 how to poach eggs?