R：使用字符串匹配将特定列的行除以 df2 的列

Question

我有一个关于两个数据帧的问题。

我有这样的数据：

df1 <- data.frame(ID = c("a","b","c","d","e"),
                  var1 = c(10,15,12,14,NA))

df2 <- data.frame(Name = c("Nr1","Nr2","Nr100","Nr76"),
                    a_xyz = c(100, 120,130,NA), 
                    b_xyz = c(150,NA,80,90), 
                    c_xyz = c(120,120,NA,140), 
                    d_xyz = c(140,130,150,180), 
                    e_xyz = c(130,120,100,150))

我想（也许是一个循环）将 df2 中列“a_xyz”的每个值除以 df1“a”的值。我想对 df2 中的每个变量执行此操作，因此我必须查找字符串匹配项以及该值是否预先存在。遗憾的是，我在 df1 和 df2 中没有相同的名称（“a”和“a_xyz”），这使得这项任务比我希望的更复杂。

生成的 df3 最后应该是这样的：

df3 <- data.frame(Name = c("Nr1","Nr2","Nr100","Nr76"),
                  a_xyz = c(10, 12, 13, NA),
                  b_xyz = c(10,NA,5.33,6), 
                  c_xyz = c(10,10,NA,1.667), 
                  d_xyz = c(10,10.83,10.71,12.85), 
                  e_xyz = c(130,120,100,150))

你们能帮帮我吗？也许我想多了，这个问题有一个简单的解决方案。

非常感谢您！

Answer 1

试试这个。您的某些最终值不正确，因此如果有其他计算定义，请告诉我。可以进行重塑和合并以获得与所需输出类似的输出：

library(dplyr)
library(tidyr)
#Code
new <- df2 %>% pivot_longer(-Name) %>%
  mutate(val=name) %>%
  separate(val,c('ID','V1'),sep="_") %>%
  left_join(df1) %>%
  mutate(Res=ifelse(!is.na(var1),value/var1,value)) %>%
  select(c(Name,name,Res)) %>%
  pivot_wider(names_from = name,values_from=Res)

输出：

# A tibble: 4 x 6
  Name  a_xyz b_xyz c_xyz d_xyz e_xyz
  <chr> <dbl> <dbl> <dbl> <dbl> <dbl>
1 Nr1      10 10     10   10      130
2 Nr2      12 NA     10    9.29   120
3 Nr100    13  5.33  NA   10.7    100
4 Nr76     NA  6     11.7 12.9    150

Answer 2

另一个解决方案是转向 df1，我认为这会导致一个相当干净的解决方案。

library(dplyr, warn.conflicts = F)
library(tidyr)

df1 <- data.frame(ID = c("a","b","c","d","e"),
                  var1 = c(10,15,12,14,NA))

df2 <- data.frame(Name = c("Nr1","Nr2","Nr100","Nr76"),
                  a_xyz = c(100, 120,130,NA), 
                  b_xyz = c(150,NA,80,90), 
                  c_xyz = c(120,120,NA,140), 
                  d_xyz = c(140,130,150,180), 
                  e_xyz = c(130,120,100,150))

df1 <- df1 %>% pivot_wider(names_from = ID, values_from = var1)

df3 <- df2 %>%
  mutate(a_xyz = a_xyz / df1$a,
         b_xyz = b_xyz / df1$b,
         c_xyz = c_xyz / df1$c,
         d_xyz = d_xyz / df1$d,
         e_xyz = e_xyz / df1$e)
df3
#>    Name a_xyz     b_xyz    c_xyz     d_xyz e_xyz
#> 1   Nr1    10 10.000000 10.00000 10.000000    NA
#> 2   Nr2    12        NA 10.00000  9.285714    NA
#> 3 Nr100    13  5.333333       NA 10.714286    NA
#> 4  Nr76    NA  6.000000 11.66667 12.857143    NA

R：使用字符串匹配将特定列的行除以 df2 的列

R: divide rows of specific columns by column of df2 with string-match

r

dataframe

data-manipulation

string-matching