Number of missing values in dataset

Question

Hi!!

I want to know how to find out the number of missing values in the dataset and how to remove them?

Thanks!

Answer 1

Missing values bring in a lot of chaos to the data. Thus, it is always important to deal with the missing values before we build any models.

Consider an example:

An employee data-set which consists of missing values:

The following code gives the number of missing values->

sum(is.na(employee))

This code deletes the missing values:

na.omit(employee)

So, you can use is.na to find the number of missing values, and na.omit to delete the missing values.

Answer 2

Missing value treatment is a 2 step process:

1. Detecting missing values: You can detect missing values using single piece of code in python <Pandas.isnull().any()>

2. Removing missing values: You can now replace the missing values within your dataset using:

• Mean Imputation: Replacing the missing values of a particular feature with mean of that particular feature
• Median Imputation: Replacing the missing values of a particular feature with median of that particular feature

Answer 3

Try this,

lapply(airquality, function(x) { sum(is.na(x)) })