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Questions - data.table

Simultaneously remove the first and last rows of a data frame until reaching a row that does not have an NA

I have a dataframe that contains NA values, and I want to remove some rows that have an NA (i.e., not complete cases). However, I only want to remove rows at the beginning and ending of the dataframe....
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AndrewGB

r

dataframe

data.table

tidyverse

na

Votes: 0

Answers: 7

Latest Answer

Another possible solution (thanks, @r2evans, for suggesting complete.cases): library(dplyr) df %>% mutate(aux = !complete.cases(.)) %>% filter(!cumall(aux)) %>% arrange(desc(var1)) ...
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PaulS

Using dplyr and data.table with get() for reusibility and shiny - good practices in R

Main question: What's the best way to pass variables to dplyr and data.table - when variables are not hard-coded but are acquired from user at run-time, as when entered from Shiny? Example 1: df <...
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IVIM

r

dplyr

data.table

Votes: 0

Answers: 0

Calculate mean difference values

I have the following data.table:- set.seed(1234332) kks <- data.table(name = c("a", "a", "b", "b", "b", "d", "d", "d"...
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Shawn Brar

r

data.table

Votes: 0

Answers: 1

Latest Answer

As pointed out in the comments, I'm not sure what you mean with "according to column loc". If you mean group by then I'd do the following (also not sure, do you want to keep the old columns ...
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TimTeaFan

Is there a way to specify the current row in R data.table

The code below creates a minimal data.table, shows the approach I am using with a for loop, and prints the desired output. library(data.table) # example data.table where "ID" corresponds to...
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3RK

r

data.table

Votes: 0

Answers: 2

Latest Answer

You can try this: f <- function(b) df[which(df2$ID %in% df2$parent_ID[b$id])]$value df2[, parent_value:= f(.BY), by=.(id = 1:nrow(df2))] Output: ID parent_ID value parent_value 1: 1 0 ...
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langtang

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