如何一次转换几个变量的类 [英] How to convert class of several variables at once
问题描述
因此,我有一个带有几个变量的数据框,这些变量是要转换为数字的字符。这些变量均以 sect1开头。我一次可以轻松完成此操作,但是我想知道是否可以一次完成所有操作。
So I have a data frame with several variable that are characters that I want to convert to numeric. Each of these variables starts with "sect1". I can do this easily one at a time, but I'm wondering if this can be accomplished all at once.
我使用以下代码。也许有更好的办法?
I've done this in a clunky way using the following code. Maybe there's a better way?
df=data.frame(sect1q1=as.character(c("1","2","3","4","5")),
sect1q2=as.character(c("2","3","4","7","8")),id=c(22,33,44,55,66),
stringsAsFactors = FALSE)
df1 = sapply(select(df,starts_with("sect1")),as.numeric)
df = select(df,-starts_with("sect1"))
df =cbind(df,df1)
推荐答案
尝试 mutate_each
和(根据@Franks的评论,%<>
运算符,以便修改 ) magrittr
包中的%
Try mutate_each
and (as per @Franks comment the %<>%
operator from the magrittr
package in order to modify in place)
library(magrittr)
df %<>% mutate_each(funs(as.numeric), starts_with("sect1"))
str(df)
# 'data.frame': 5 obs. of 3 variables:
# $ sect1q1: num 1 2 3 4 5
# $ sect1q2: num 2 3 4 7 8
# $ id : num 22 33 44 55 66
或者,使用 data.table
包,您可以修改 使用:=
运算符
Alternatively, using data.table
package, you could modify your data in place using the :=
operator
library(data.table)
indx <- grep("^sect1", names(df), value = TRUE)
setDT(df)[, (indx) := lapply(.SD, as.numeric), .SDcols = indx]
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