Making a List out of a Column in R

user_17119663 0
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I am Trying to make a list out of a certain Column of my DataFrame.

But it should depend on another column, if it schould be added to the list.

So for example if the dataframe is:

names <- c('Word1','Word2','Word3')
quant <- c(5, NA, 10)

my.data <- data.frame(names, quant)

Now I would only like to List the words with a quantity and leave out the ones with "NA". Is there a smart and fast way to do this? The final List in this case should be (Word1, Word3)

Thank you very much for your help. I am a beginner with R and my only soution would be a loop going through the dataFrame and check for every value.

data-manipulation dataframe r
3 Answers

We could use complete.cases. na.omit removes all NA's. With complete.cases we are able to partially select the columns. See my.data[complete.cases(my.data[1,1]),] vs. my.data[complete.cases(my.data[1:2,2]),]:

my.data[complete.cases(my.data),]

  names quant
1 Word1     5
3 Word3    10

and is faster:

library(microbenchmark)

microbenchmark(
  na.omit(my.data)$names,
  my.data[complete.cases(my.data),]
)

Unit: microseconds
                               expr min    lq   mean median   uq   max neval cld
             na.omit(my.data)$names  46 46.95 50.457  47.60 49.4  90.9   100   b
 my.data[complete.cases(my.data), ]  22 22.80 25.522  23.65 24.3 133.5   100  a
user_133216470

Or may use subset with is.na and negate (!)

 subset(my.data, !is.na(quant))
  names quant
1 Word1     5
3 Word3    10
user_37322710

Is this what you are looking for?

na.omit(my.data)

  names quant
1 Word1     5
3 Word3    10
user_79768380
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