Question

我有两个数据库：

dfgenus<- c("Coragyps" ,"Elanus", "Elanus", "Patagioenas", "Crotophaga")

如此

dfgenus
       Genus
1     Coragyps
2       Elanus
3       Elanus
4  Patagioenas
5   Crotophaga

和

family <-c("Cathartidae", "Accipitridae","Cuculidae", "Columbidae","Psittacidae")
Genus <- c("Coragyps" ,"Elanus", "Crotophaga", "Patagioenas", "Pyrrhura")

sacc<- data.frame(family, genus)
##Sacc db rows are in the right order (the genus belongs to its taxonomic family)

sacc
  family       Genus
1  Cathartidae    Coragyps
2 Accipitridae      Elanus
3    Cuculidae  Crotophaga
4   Columbidae Patagioenas
5  Psittacidae    Pyrrhura

在有关“ sacc”的信息之后，如何为“ dbgenus”中的每个属添加正确的家族？

我一直未尝试：

for (i in length(dfgenus)){
if (identical(sacc[i], dfgenus[i])) {
    df$family[i] <- sacc$family[i] 
}   else {
        i-1 
} 
print(df$family) 
}

输出应为：

df
        family       Genus
1  Cathartidae    Coragyps
2 Accipitridae      Elanus
3 Accipitridae      Elanus
4   Columbidae Patagioenas
5    Cuculidae  Crotophaga

Answer 1

使用dplyr解决方案：

library(dplyr)

dbgenus<- data.frame(genus = c("Coragyps" ,"Elanus", "Elanus", "Patagioenas", "Crotophaga"))
family <-c("Cathartidae", "Accipitridae","Cuculidae", "Columbidae","Psittacidae")
genus <- c("Coragyps" ,"Elanus", "Crotophaga", "Patagioenas", "Pyrrhura")

sacc<- data.frame(family, genus)

dbgenus %>% left_join(sacc)

Answer 2

有几种方法可以实现您的结果。它们都不应该涉及for循环：）

如果将dfgenus做成一个数据帧（只有一列），则可以研究merge()函数或dplyr包中的联接函数。

但是使用现有数据，您可以使用match()：

newdf <- data.frame(Genus  = dfgenus, 
                    Family = sacc[match(dfgenus, sacc$Genus), "family"])

        Genus       Family
1    Coragyps  Cathartidae
2      Elanus Accipitridae
3      Elanus Accipitridae
4 Patagioenas   Columbidae
5  Crotophaga    Cuculidae

match从sacc返回匹配的行号，然后将其用于从family列返回子集。

根据条件合并

2 个答案: