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# How to Calculate the Mean of Multiple Columns in R

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 of only numeric 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```