CODEWITHSUNDEEP
rselectmultiple-columnsnames
KKhosra
KKhosra

Reputation: 173

Selecting Multiple Columns by Name without having to Type each name

How do I select multiple columns by name without having to type out each name.

For example I have the following code: 

CTDB[, c(
"ENJOY_TV_RADIO_CHILD", 
"ENJOY_FMLY_CLOSE_FRND_CHILD", 
"ENJOY_HOBBIES_CHILD", 
"ENJOY_FAV_MEAL_CHILD",
"ENJOY_SHOWER_CHILD", 
"ENJOY_SCENT_CHILD", 
"ENJOY_PPL_SMILE_CHILD", 
"ENJOY_LOOK_SMART_CHILD", 
"ENJOY_READ_CHILD", 
"ENJOY_FAV_DRINK_CHILD", 
"ENJOY_SMALL_THINGS_CHILD", 
"ENJOY_LANDSCAPE_CHILD", 
"ENJOY_HELP_OTHR_CHILD", 
"ENJOY_PRAISE_CHILD")] <-revalue(as.matrix(CTDB[, c(
"ENJOY_TV_RADIO_CHILD", 
"ENJOY_FMLY_CLOSE_FRND_CHILD",
"ENJOY_HOBBIES_CHILD", 
"ENJOY_FAV_MEAL_CHILD", 
"ENJOY_SHOWER_CHILD", 
"ENJOY_SCENT_CHILD", 
"ENJOY_PPL_SMILE_CHILD", 
"ENJOY_LOOK_SMART_CHILD", 
"ENJOY_READ_CHILD", '
"ENJOY_FAV_DRINK_CHILD", 
"ENJOY_SMALL_THINGS_CHILD", 
"ENJOY_LANDSCAPE_CHILD", 
"ENJOY_HELP_OTHR_CHILD", 
"ENJOY_PRAISE_CHILD")]), c("0"=3, "1"=2, "2"=1, "3"=0))

All the columns are in order but instead of selecting by number like below 

CTDB[,74:87] <-revalue(as.matrix(CTDB[,74:87]), c("0"=3, "1"=2, "2"=1, "3"=0))

I would like to select by the name of the column.

Thank you!

Upvotes: 0

Views: 1402

Answers (2)

Calum You
Calum You

Reputation: 15062

If you need to do this as part of a pipe, you can also use dplyr::select and its helper functions in two equivalent ways, including one that can avoid regular expressions:

CTBD %>% select(matches("^ENJOY.*CHILD$"))
CTBD %>% select(intersect(starts_with("ENJOY"), ends_with("CHILD")))

Upvotes: 1

Onyambu
Onyambu

Reputation: 79188

You should use grep or grepl

CTBD[,grep("^ENJOY.*CHILD$",colnames(CTBD)]

or

CTBD[,grepl("^ENJOY.*CHILD$",colnames(CTBD)]

Upvotes: 3

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