Learn R: Aggregates

Learn the basics of aggregate functions in R with dplyr, which let us calculate quantities that describe groups of data.

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Key Concepts

Review core concepts you need to learn to master this subject

dplyr package

groub_by() with mutate()

dplyr group_by()

filter() with group_by()

dplyr summarise()

dplyr package

The dplyr package provides functions that perform data manipulation operations oriented to explore and manipulate datasets. At the most basic level, the package functions refers to data manipulation “verbs” such as select, filter, mutate, arrange, summarize among others that allow to chain multiple steps in a few lines of code. The dplyr package is suitable to work with a single dataset as well as to achieve complex results in large datasets.

Aggregates in R

Lesson 1 of 1

1
Introduction
In this lesson you will learn about aggregates in R using dplyr. An aggregate statistic is a way of creating a single number that describes a group of numbers. Common aggregate statistics include m…
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2
Calculating Column Statistics
In this exercise, you will learn how to combine all of the values from a column for a single calculation. This can be done with the help of the dplyr function summarize(), which returns a new da…
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3
Calculating Aggregate Functions I
When we have a bunch of data, we often want to calculate aggregate statistics (mean, standard deviation, median, percentiles, etc.) over certain subsets of the data. Suppose we have a grade book w…
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4
Calculating Aggregate Functions II
Sometimes, we want to group by more than one column. We can do this by passing multiple column names as arguments to the group_by function. Imagine that we run a chain of stores and have data abo…
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5
Combining Grouping with Filter
While group_by() is most often used with summarize() to calculate summary statistics, it can also be used with the dplyr function filter() to filter rows of a data frame based on per-group metrics….
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6
Combining Grouping with Mutate
group_by() can also be used with the dplyr function mutate() to add columns to a data frame that involve per-group metrics. Consider the same educational technology company’s enrollments table fro…
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7
Review
This lesson introduced you to aggregates in R using dplyr. You learned: * How to calculate summary statistics with summarize() * How to perform aggregate statistics over individual rows with the…
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