Grouping columns and creating a list output

Question

I am new to R. I have a R dataframe of following structure:

     164_I_.CEL 164_II.CEL 183_I.CEL 183_II.CEL 2114_I.CEL
   1       4496       5310      4492       4511       2872
   2        181        280       137        101         91
   3       4556       5104      4379       4608       2972
   4        167        217        99         79         82
   5         89        110        69         58         47

I want to group the columns which have "_I.CEL" in the column name.

I need a list output like NI, NI, I, NI, I

where NI means Not I.

Possible duplicate of [How to drop columns by name pattern in R?](https://stackoverflow.com/questions/15666226/how-to-drop-columns-by-name-pattern-in-r) — divibisan, Mar 08 '19 at 01:19

Ronak Shah · Accepted Answer · 2019-03-06T09:23:16.700

0

A combination of ifelse and grepl looking for the required pattern in the column names.

ifelse(grepl("_I\\.CEL", names(df1)), "I", "NI")
#[1] "NI" "NI" "I"  "NI" "I"

where df1 is your data frame.

Or use fixed = TRUE

ifelse(grepl("_I.CEL", names(df1), fixed = TRUE), "I", "NI")

edited Mar 06 '19 at 09:23

answered Mar 06 '19 at 08:50

Ronak Shah

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Grouping columns and creating a list output

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