Question

我想使用if else语句更改许多变量。这是我正在使用的代码来完成工作：

df <- df %>%
  mutate(p = ifelse(gender == 0, p, ifelse(gender==1, 100 - p,NA)),
         t = ifelse(gender == 0, t, ifelse(gender==1, 100 - t,NA)),
         c = ifelse(gender == 0, c, ifelse(gender==1, 100 - c,NA)),
         s = ifelse(gender == 0, s, ifelse(gender==1, 100 - s,NA)),
         i = ifelse(gender == 0, i, ifelse(gender==1, 100 - i,NA)))

但是，是否有使用tidyverse进行这些多项更改的更紧凑的方法？

Answer 1

您不必每次都必须输入列名称的情况下才将函数分别应用于每个列，而可以使用apply（..）为您执行此操作。

一些数据：

n <- 10
df <- data.frame(matrix(round(rnorm(n*5), 0), ncol= 5))
variablenames <- c("p", "t", "c", "s", "i")
names(df) <- variablenames
df$gender <- sample(0:1, n, replace= TRUE)

您的函数和建议的函数给出相同的结果

df1 <- df %>%
  mutate(p = ifelse(gender == 0, p, ifelse(gender==1, 100 - p,NA)),
         t = ifelse(gender == 0, t, ifelse(gender==1, 100 - t,NA)),
         c = ifelse(gender == 0, c, ifelse(gender==1, 100 - c,NA)),
         s = ifelse(gender == 0, s, ifelse(gender==1, 100 - s,NA)),
         i = ifelse(gender == 0, i, ifelse(gender==1, 100 - i,NA)))

df2 <- apply(df[ , variablenames], 2, function(x){
  ifelse(df$gender == 0, x, ifelse(df$gender==1, 100 - x,NA))
})

df2 <- cbind.data.frame(df2, df$gender)

all(df1 == df2)
TRUE

通过条件语句更改多个变量

1 个答案: