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Often you may want to calculate the mean of multiple columns in R. Fortunately you can easily do this by using theÂ **colMeans()Â **function.

colMeans(df)

The following examples show how to use this function in practice.

**Using colMeans() to Find the Mean of Multiple Columns**

The following code shows how to use theÂ **colMeans()Â **function to find the mean of every column in a data frame:

#create data frame df #find mean of each column colMeans(df) var1 var2 var3 var4 3.2 5.4 5.2 4.2

We can also specifyÂ *whichÂ *columns to find the mean for:

#find the mean of columns 2 and 3 colMeans(df[ , c(2, 3)]) var2 var3 5.4 5.2 #find the mean of the first three columns colMeans(df[ , 1:3]) var1 var2 var3 3.2 5.4 5.2

If there happen to be some columns that arenâ€™t numeric, you can use sapply() to specify that youâ€™d only like to find the mean of columns that are numeric:

#create data frame df #find mean ofonlynumeric columns colMeans(df[sapply(df, is.numeric)]) var1 var2 var3 var4 3.2 5.4 5.2 4.2

And if there happen to be missing values in any columns, you can use the argument **na.rm=TRUEÂ **to ignore missing values when calculating the means:

#create data frame with some missing values df #find mean of each column and ignore missing values colMeans(df, na.rm=TRUE) var1 var2 var3 var4 3.0 5.4 5.2 3.0

**Additional Resources**

How to Loop Through Column Names in R

How to Sum Specific Columns in R