In this post, we will discuss about a brief intro to dplyr package in R. dplyr is a part of Tidyverse collection of R packages used for data science. The Tidyverse contains other packages as well, like ggplot2 , readr, tidyr, purr etc.
Most datasets contain more information than they display. dplyr is a package that can help you access that information.
dplyr introduces a grammar of data manipulation. It has 5 simple functions that you can use to reveal new variables, new observations, and new ways to describe data.You can also use these functions to make a subset of the data, do group wise operations.
dplyr is fast, and the key pieces of dplyr are written in C++. This means that we would get speed of C++ and ease of R language.
Let’s learn how to use dplyr to solve any data related task.
how to install dplyr?
First, lets install dplyr in your R-Studio console.
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install.packages("dplyr") |
You can also install Tidyverse package in order to use dplyr. As dplyr is part of Tidyverse, it will get installed automatically.
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install.packages("tidyverse") |
Let’s now install hflights package. We shall use this dataset to learn about dplyr.
Let’s load these two packages using library function.Once hflights is loaded, it will be available as a dataframe in your R console. Read this blog post to understand about dataframes
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library(dplyr) library(hflights) |
head() function in dplyr
Use head() function to see the first few rows of a dataframe.
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head(hflights) |
summary() function in dplyr
summary() function is used to see higher level info about any dataset.Try using summary() to find summary statistics.
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summary(hflights) |
The variables are stored in the columns, whereas the observations are stored in the rows of this data set.
If you go fully through the output of the summary() function, you can see that, this hflights data set is relatively large.It contains 227496 rows !!
what is tbl?
dplyr can help you to look at a dataset thoroughly.It provides a new datastructure for R, the tbl(pronounced the tibble).
A tbl is just a different type of dataframe.
tbl_df()
To turn hflights dataframe to a tibble (tbl) , you need to run tbl_df(hflights)
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hflights <- tbl_df(hflights) |
Then when we see hflights in R console, it will cut out the superfluous columns and show the results neatly. It will tell the dimensions of the dataset, the names and data types of each column present in the dataset. The best feature is that tbl will size the output according to the size of your screen !
Note that even if we convert a dataframe to a tbl, you can still modify the tbl as if it were a dataframe.
Whatever functions we can use on a dataframe, can be used on a tbl as well.
glimpse()
We can use glimpse() to see the datatypes and initial values for each column in your dataset.
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glimpse(hflights) |
Use the class function to verify that a tbl is internally a dataframe.
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> class(hflights) [1] "tbl_df" "tbl" "data.frame" |
We will learn to use dplyr tbl structure, its pipe operator, which are two features to save a lot of time.We will learn to use dplyr to access data stored in a database.As you can see, with dplyr, R has become faster, bigger and better.
Any questions on dplyr, feel free to ask in the comments section below.