CODEWITHSUNDEEP
r
ZM-
ZM-

Reputation: 104

Effective way of filtering a list

I am trying to extract subsets of a dictionary word list based on a certain criteria.

The n selected words in each set/vector must have the same 1st, 3rd and 4th character as the ith

More concretely, consider the list

KHRSTT,  KHRSTK,  KKTLTK, TTLTTK, TKLTER

From this list, I want a set of all words with the 1st, 3rd, 4th character is the same

{
  {KHRSTT, KHRSTK},
  {TTLTTK, TKLTER}
}

or 

{
  {KHRSTT, KHRSTK},
  {TTLTTK, TKLTER},
  {KKTLTK}
}

Upvotes: 0

Views: 61

Answers (1)

Anil Kumar
Anil Kumar

Reputation: 445

list  <- list('KHRSTT',  'KHRSTK',  'KKTLTK', 'TTLTTK', 'TKLTER')

a <- matrix("0",nrow = length(list),ncol= length(list))  

for (x in 1:length(list)){
    for (y in 1:length(list)){
        if( y != x){
            if(substr(list[x], start = 1, stop = 1) == substr(list[y], start = 1, stop = 1) &
               substr(list[x], start = 3, stop = 3) == substr(list[y], start = 3, stop = 3) &
               substr(list[x], start = 4, stop = 4) == substr(list[y], start = 4, stop = 4)){
                 a[x,x] = as.character(list[x])
                 a[x,y] = as.character(list[y])
                }
        }
    }
}

print(a)

Upvotes: 1

Related Questions