使用 dplyr 包 R 改变 data.frame 或 tibble 中选定的列

Question

我想mutate一次将一个函数应用于多个列。列以特定字符串开头，这就是它们的标识方式。我还想知道如何将其应用于由索引标记的列的解决方案，即。data_fake[3:4]. 目标是删除所有非数字字符并将值转换为数字。不能让它伤心地工作。代码末尾给出了所需的结果。非常感谢。

data_fake <- data.frame(c("1","2","NA","3,","2","1 only"),c(1,2,3,4,5,6),
                        c("23","3 bundles","4","5","NA","1"), c("3","5 packs","6","78","7","8"))
colnames(data_fake) <- c("AB foo ab", "AB foo bc", "CD foo ab","CD foo bc")

data_fake <- as_tibble(data_fake)

data_fake %>%
        select(starts_with("CD foo")) %>% 
        mutate(as.numeric(gsub("[^0-9]", "")))

data_fake_results <- as_tibble(data.frame(c("1","2","NA","3,","2","1 only"),c(1,2,3,4,5,6),
                        c(23,3,4,5,NA,1), c(3,5,6,78,7,8)))

Answer 1

我们可以用 mutate_at

library(tidyverse)
data_fake %>%
    mutate_at(vars(3:4), funs(as.numeric(str_remove(., "\\s+[a-z]+"))))

或使用 parse_number

data_fake %>%
     mutate_at(3:4, parse_number)

如果我们想匹配列名 mutate_at

data_fake %>% 
    mutate_at(vars(starts_with("CD")), parse_number)