根据条件删除选定的案例

Question

I would like to remove cases from a data frame based on whether they contain a particular pattern. For example in the data frame below I would like to remove all the rows that contain (Intercept), iyeareducc, ibphtdep and gender_R22 (or alternatively selecting the rows that contain _carrier1 or adri).

                               OR        CI    P
apoee4_carrier.(Intercept)     1.96 0.97-3.94 0.06
apoee4_carrier.apoee4_carrier1 1.03 0.77-1.37 0.84
apoee4_carrier.iyeareducc      0.86  0.82-0.9 0.00
apoee4_carrier.ibphdtdep       1.01 0.96-1.05 0.81
apoee4_carrier.gender_R22      0.87 0.67-1.12 0.28
BDNF_carrier.(Intercept)       2.05 1.01-4.14 0.04
BDNF_carrier.BDNF_carrier1     0.87 0.66-1.14 0.33
BDNF_carrier.iyeareducc        0.86  0.82-0.9 0.00
BDNF_carrier.ibphdtdep         1.00 0.96-1.05 0.82
BDNF_carrier.gender_R22        0.87 0.67-1.12 0.28
adri.(Intercept)               1.60 0.78-3.31 0.20
adri.adri                      1.03    1-1.06 0.04
adri.iyeareducc                0.89 0.84-0.94 0.00
adri.ibphdtdep                 1.00 0.95-1.04 0.87
adri.gender_R22                0.87 0.67-1.12 0.27

While I could use a sequence to subset out the rows I require, like so

dat[(seq(2,nrow(dat),5)),]
                                 OR        CI    P
apoee4_carrier.apoee4_carrier1 1.03 0.77-1.37 0.84
BDNF_carrier.BDNF_carrier1     0.87 0.66-1.14 0.33
adri.adri                      1.03    1-1.06 0.04

this will only work if the sequence is the same throughout the entire dataframe, which may not be necessarily the case as this data frame is created from a list of data frames that have been rbind together.

Thanks.

Answer 1

You can use grep to select the rows you want/don't want:

dat[-grep("Intercept|iyeareducc|ibphdtdep|gender", rownames(dat)),]

grep returns the row numbers of the rows for which the row names contain at least one of your search strings (the | between each string means "OR"). Putting a minus sign in front of grep tells R to return only the rows of dat that are not returned by grep .