CODEWITHSUNDEEP
rsubset
Cassia Camillo
Cassia Camillo

Reputation: 3

Delete rows in R based on length of a column

I have a data set in R that has 4 columns: size of turtle hatchlings, number of nests, years, beach.

I want to create a new data frame, excluding the nests for which I measured less than 10 hatchlings. So I need to exclude rows based on the length of the column Size, for unique combinations of "Year", "Beach" and "Nest". Thank you.

Upvotes: 0

Views: 153

Answers (1)

akrun
akrun

Reputation: 887951

We can use data.table. Convert the 'data.frame' to 'data.table' (setDT(df1)), grouped by 'Year', 'Beach', 'Nest', we subset the groups where the length of unique elements of "Hatchling_Number" is greater than or equal to 10

library(data.table)
setDT(df1)[, if(uniqueN(Hatchling_Number)>=10) .SD, by = .(Year, Beach, Nest)]

or in case there are no duplicate "Hatchling_Number" per each group, we can use .N >=10 for subsetting.

setDT(df1)[, if(.N >=10) .SD, by = .(Year, Beach, Nest)]

Upvotes: 2

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