CODEWITHSUNDEEP
r
user11626803
user11626803

Reputation:

Remove empty list elements in R

Since most of the words I search return an empty list, I'd like to keep only those which give a result.

> assocs<-findAssocs(dtm,names(freq[1:5]),0.5)
> assocs
$cuffie
numeric(0)

$auricolari
    colora  controlli interrotta operazione      verrà 
      0.52       0.52       0.51       0.51       0.50 

$qualità
numeric(0)

$suono
numeric(0)

$ricarica
         colora      interrotta      operazione           verrà     addentrarmi          attira 
           0.57            0.56            0.55            0.54            0.53            0.53 
       attirano        avanzati  consigliarveli      consultato        iniziare   interromperne 
           0.53            0.53            0.53            0.53            0.53            0.53 
    inutilmente        mettersi   negativamente      reinserire       ritornare siribixbygoogle 
           0.53            0.53            0.53            0.53            0.53            0.53 
      specifico         ventina       collocare 
           0.53            0.53            0.52

Desired Output:

> assocs

$auricolari
    colora  controlli interrotta operazione      verrà 
      0.52       0.52       0.51       0.51       0.50 

$ricarica
         colora      interrotta      operazione           verrà     addentrarmi          attira 
           0.57            0.56            0.55            0.54            0.53            0.53 
       attirano        avanzati  consigliarveli      consultato        iniziare   interromperne 
           0.53            0.53            0.53            0.53            0.53            0.53 
    inutilmente        mettersi   negativamente      reinserire       ritornare siribixbygoogle 
           0.53            0.53            0.53            0.53            0.53            0.53 
      specifico         ventina       collocare 
           0.53            0.53            0.52

By doing so I could search on more words without having returned an enormous list.

The library used for findassocs() is tm.

The output is:

> class(assocs)
[1] "list"

I have tried this:

for (i in 1:5){
  if (length(assocs[[i]])==0){
    new_assocs[j]=assocs[i]
    j=j+1
  }
}

But the output was like this:

> new_assocs
[[1]]
numeric(0)

[[2]]
numeric(0)

[[3]]
numeric(0)

[[4]]
numeric(0)

[[5]]
numeric(0)

Thank you all in advance.

Upvotes: 1

Views: 578

Answers (2)

Stibu
Stibu

Reputation: 15907

The function lengths() returns the number of elements (i.e., the length) for each element in a list. So you can do this:

assocs[lengths(assocs) >= 1]

This is, of course, basically the same answer as Daniel O's, but it is somewhat simpler and, for large lists, more efficient.

Upvotes: 1

Daniel O
Daniel O

Reputation: 4358

You can check the length since numeric(0) has no length

assocs[sapply(assocs, function(x) length(x) >= 1)]

Upvotes: 2

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