2020.06.10.case_when_tutorial.R

# Hello World 

# Below is a case when tutorial 


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# Libraries
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library(dplyr)

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# Table of Contents
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# 1.0 Introduction
# 2.0 Bringing in Data
# 3.0 Creating a new expression

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# 1.0 Introduction
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# Case when in R can be executed with case_when() 
#   function in dplyr package. Dplyr package is provided with case_when() 
#   function which is similar to case when statement in SQL.

# We will be using iris data to depict the example of case_when() 
#   function.

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# 2.0 My data 
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mydata2 <-iris 
head(mydata2)



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# 3.0 New Conditional Statement 
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# Create new/additional variable 
# species_new using the mutate function and case when statement

mydata2 %>% mutate(species_new = case_when(is.na(Species) ~ "missing",
                                           Species=="setosa" ~ "setosa_new",
                                           Species=="versicolor" ~ "versicolor_new",
                                           Species=="virginica" ~ "virginica_new",
                                           TRUE ~ "others"))
# you can use variables directly within the case_when()wrapper
# TRUE equivalent to ELSE statement


mydata2
head(mydata2)













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