How to select a specific element on a list of character based on its position

Question

I am a new R user and I need some help.

I have a dataframe that look like this :

Type                                     ID
pink-blue-blue-green-END                 125
blue-pink-END                            145
green-green-pink-END                     489
green-pink-blue-END                      478
pink-green-green-blue-END                546

And I want all the rows where "blue" is before "pink", the results would be

Type                                     ID
pink-blue-blue-green-END                 125
green-pink-blue-END                      478
pink-green-green-blue-END                546

And I would like to know another tips :) How I can do to delete all the "green" inside the list of character and having for example for the 1st row :

pink-blue-blue-END 

Thanks for your help

Answer 1

We can use grep to match the word "pink" followed by one or more characters followed by word "blue". Note that \\b signify the word boundary

df1[grepl("\\bpink\\b-.*\\bblue\\b", df1$Type),]
#                       Type  ID
#1  pink-blue-blue-green-END 125
#4       green-pink-blue-END 478
#5 pink-green-green-blue-END 546

For the second case, use gsub

df1$Type <- gsub("green-", "", df1$Type)