过滤行值以一组模式结尾的行

Question

I have a data set as follows

File_name     Folder
ord.cpp        1
rod.ibo        1
ppol.h         2
lko.cpp        3
rto.cp         3
tax.mo         2
t_po..lo.cpp   4

I need to subset this data set so that only rows where File_name ends with ".cpp" or ".h" is present in the data set

Answer 1

Use grepl for a base R option:

df_subset <- df[grepl("\\.(?:cpp|h)$", df$File_name), ]
df_subset

     File_name Folder
1      ord.cpp      1
3       ppol.h      2
4      lko.cpp      3
7 t_po..lo.cpp      4

Demo

Answer 2

A dplyr and stringr solution:

df %>%
 filter(str_detect(File_name, ".cpp|.h"))

     File_name Folder
1      ord.cpp      1
2       ppol.h      2
3      lko.cpp      3
4 t_po..lo.cpp      4

Or with just dplyr :

df %>%
 filter(grepl(".cpp|.h", File_name))

     File_name Folder
1      ord.cpp      1
2       ppol.h      2
3      lko.cpp      3
4 t_po..lo.cpp      4

Answer 3

We can also use file_ext function from tools package to get file extensions of the file and then use it to subset data frame.

library(tools)
df[file_ext(df$File_name) %in% c("cpp", "h"), ]

#     File_name Folder
#1      ord.cpp      1
#3       ppol.h      2
#4      lko.cpp      3
#7 t_po..lo.cpp      4

Answer 4

Base R solution:

# Looking for a string eding with .cpp or .h
df[endsWith(df$File_name,(".cpp"))|endsWith(df$File_name,(".h")),]

Output:

     File_name Folder
1      ord.cpp      1
3       ppol.h      2
4      lko.cpp      3
7 t_po..lo.cpp      4