Missing Values
You can check if a dataset has missing values per column using the apply()
function.
- The first argument of
apply()
is the dataframe you are inspecting, in this case,studentnetworkdata
. - The second argument indicates whether operations should be performed row-wise (1) or column-wise (2).
- The third argument is the function applied to each row or column. You specify it by writing
function(x) ...
where...
indicates the operation.
You want to count the number of missing values in each column. Usesum(is.na(x))
to find all the missing values and count them.
How many columns in studentnetworkdata
have missing values?
This exercise is part of the course
Predictive Analytics using Networked Data in R
Hands-on interactive exercise
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