CODEWITHSUNDEEP
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Ernsthaft
Ernsthaft

Reputation: 177

R: Calculate standard deviation in cols in a data.frame despite of NA-Values

Good Morning, I got a lot of data and i have to calculate with it. There are 25 columns (variables) and each column contains thousands of values. But also missing values. I calculated the mean with

colMeans(df, na.rm = TRUE)

How can i calculate the sd of each column and ignore the NA-values?

Upvotes: 3

Views: 37715

Answers (4)

Cindy Wang
Cindy Wang

Reputation: 11

sd(variablenname,na.rm=TRUE)

This works for me. Replace "variablename" with the variable you use.

Upvotes: 0

Dan
Dan

Reputation: 1

As the functioin summarise_each() has been deprecated, here is an up-to-date example using dplyr:

df1 %>% summarise_all(funs(sd(., na.rm = FALSE)))

Upvotes: 0

Sotos
Sotos

Reputation: 51592

You can try,

apply(df, 2, sd, na.rm = TRUE)

As the output of apply is a matrix, and you will most likely have to transpose it, a more direct and safer option is to use lapply or sapply as noted by @docendodiscimus,

sapply(df, sd, na.rm = TRUE)

Upvotes: 12

akrun
akrun

Reputation: 887541

If we convert to matrix, colSds from matrixStats can be used

library(matrixStats)
colSds(as.matrix(df), na.rm=TRUE)

Or we can use summarise_each from dplyr

library(dplyr)
df1 %>%
    summarise_each(funs(sd(., na.rm=TRUE)))

Upvotes: 3

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