如何在 dplyr::filter 中使用变量? [英] How to use a variable in dplyr::filter?

问题描述

我有一个与数据框中的列同名的变量:

I have a variable with the same name as a column in a dataframe:

df <- data.frame(a=c(1,2,3), b=c(4,5,6))
b <- 5

我想获取 df$b == b 的行，但 dplyr 将其解释为 df$b == df$b:

I want to get the rows where df$b == b, but dplyr interprets this as df$b == df$b:

df %>% filter(b == b) # interpreted as df$b == df$b
#   a b
# 1 1 4
# 2 2 5
# 3 3 6

如果我更改了变量名，它会起作用:

If I change the variable name, it works:

B <- 5
df %>% filter(b == B) # interpreted as df$b == B
#   a b
# 1 2 5

我想知道是否有更好的方法来告诉 filter b 引用外部变量.

I'm wondering if there is a better way to tell filter that b refers to an outside variable.

推荐答案

您可以使用 get 函数从环境中获取变量的值.

You could use the get function to fetch the value of the variable from the environment.

df %>% filter(b == get("b")) # Note the "" around b

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