[英]R - keep only columns with column names that match a string
I am relatively new to R and I've had a lot of luck finding answers on here, but this one has me stumped after 2 days of trying things.我对 R 比较陌生,我很幸运在这里找到了答案,但是在尝试了 2 天之后,这个问题让我难倒了。
I have a dataframe with column names like this:我有一个列名的数据框,如下所示:
TargetID sample1.beta sample1.avg sample1.error sample1.pval sample2.beta sample2.avg sample2.error sample2.pval TargetID sample1.beta sample1.avg sample1.error sample1.pval sample2.beta sample2.avg sample2.error sample2.pval
This repeats for thousands of samples.这对数千个样本重复。 I need to create multiple separate data frames for each piece of data: one for beta, one for avg, one for error, one for pval.
我需要为每条数据创建多个单独的数据框:一个用于 beta,一个用于 avg,一个用于错误,一个用于 pval。 I also need to keep the 1st column with the TargetID in all data frames.
我还需要在所有数据框中保留带有 TargetID 的第一列。 The resulting data frames would have column names like:
生成的数据框将具有如下列名:
TargetID sample1.beta sample2.beta sample3.beta TargetID sample1.beta sample2.beta sample3.beta
TargetID sample1.pval sample2.pval sample3.pval目标ID sample1.pval sample2.pval sample3.pval
etc.等。
I have found answers for subsetting data frames but they don't seem to apply to selecting all columns that contain a specific string (and keeping the 1st column).我找到了对数据框进行子集化的答案,但它们似乎不适用于选择包含特定字符串的所有列(并保留第一列)。
I've also been exploring whether this is better done with the txt file before I import into R with awk.在使用 awk 导入到 R 之前,我也一直在探索使用 txt 文件是否更好地完成此操作。
Use grepl
or grep
in the second position of "[" with a pattern that includes TargetID
and the subset string applied to names(dfrm_name)
:在 "[" 的第二个位置使用
grepl
或grep
,其模式包含TargetID
和应用于names(dfrm_name)
的子集字符串:
avg_sub <- dfrm[ , grepl( "^TargetID|avg$", names(dfrm) ]
The "^" pattern matches the beginning of a string, while the "$" pattern matches the end of a string. “^”模式匹配字符串的开头,而“$”模式匹配字符串的结尾。
You can try (as you don't supply example data using mtcars
):您可以尝试(因为您不使用
mtcars
提供示例数据):
library(dplyr)
# select the column mpg and all the columns containing an r
head(mtcars %>% select(mpg, contains("r")))
mpg drat gear carb
Mazda RX4 21.0 3.90 4 4
Mazda RX4 Wag 21.0 3.90 4 4
Datsun 710 22.8 3.85 4 1
Hornet 4 Drive 21.4 3.08 3 1
Hornet Sportabout 18.7 3.15 3 2
Valiant 18.1 2.76 3 1
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