Select columns based on string match - dplyr select

Question

I have a data frame   data   with lots and lots of columns  Some of the columns contain a certain string   search string     How can I use dplyr  select   to give me a subset including only the columns that contain the string   I tried     columns as boolean vector select data  grepl  search string  colnames data       columns as vector of column names names  select data  colnames data  grepl  search string  colnames data        Neither of them work   I know that select   accepts numeric vectors as substitute for columns e g    select data 5 7 9 20    But I don t know how to get a numeric vector of columns IDs from my grepl   expression

User · Answer

You can try   select data  matches  search string      It is more general than contains - you can use regex  e g   one string or the other     For more examples  see  http   rpackages ianhowson com cran dplyr man select html

User · Answer

No need to use select just use   instead  data  grepl  search string   colnames data      Let s try with iris dataset   gt iris  grepl  Sepal   colnames iris      Sepal Length Sepal Width 1          5 1         3 5 2          4 9         3 0 3          4 7         3 2 4          4 6         3 1 5          5 0         3 6 6          5 4         3 9

User · Answer

Within the dplyr world  try   select iris contains  Sepal      See the Selection section in  select for numerous other helpers like starts with  ends with  etc

User · Answer

Based on Piotr Migdals response I want to give an alternate solution enabling the possibility for a vector of strings  myVectorOfStrings  lt - c  quot foo quot    quot bar quot   matchExpression  lt - paste myVectorOfStrings  collapse    quot   quot      1   quot foo bar quot  df   gt   select matches matchExpression    Making use of the regex OR operator     ATTENTION  If you really have a plain vector of column names  and do not need the power of RegExpression   please see the comment below this answer  since it s the cleaner solution

[r] Select columns based on string match - dplyr::select

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