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Joining observation units with dplyr

Today I would like to show examples of different ways you can join data frames. Let's define and display them first. In first data.frame I will collect some information's about certain. It will contain name, high and nationality.

df1<-data.frame(name=c("Ania","Marek","Kamil","Joanna","Patrice"),high=c(178,190,175,168,175),nationality=c("polish","polish","polish","polish","french"))
df1
      name high nationality
1    Ania   178      polish
2   Marek   190      polish
3   Kamil   175      polish
4  Joanna   168      polish
5 Patrice   175      french

In second data.frame I will put observation about other group, containing their name and weight. What does this two data.frame have in common ? We can see that both contain column with the name of the person and what is more some person like Ania and Patrice are being describe in both data.frame. 

df2<-data.frame(name=c("Ania","Julia","Patrice","Jim"),weight=c(67,55,75,75)) 
df2 
       name weight
1    Ania     67
2   Julia     55
3 Patrice     75
4     Jim     75

Let's see now different possibilities of joining these elements:
library(dplyr)
inner_join(df1,df2) 

Inner_join() will return observations which are in both df1 and df2. All columns both from df1 and df2 will be present.

Joining, by = "name"
     name high nationality weight
1    Ania   178      polish     67
2 Patrice   175      french     75

left_join(df1,df2) 
Left_join() will return columns of df1 and df2 containing unique observation of df1 and those which exists both in df1 and df2.

Joining, by = "name"
     name high nationality weight
1    Ania   178      polish     67
2   Marek   190      polish     NA
3   Kamil   175      polish     NA
4  Joanna   168      polish     NA
5 Patrice   175      french     75

right_join(df1,df2) 

Right_join() will return columns of df1 and df2 containing unique observations of df2 and those which exists both in df1 and df2.

joining, by = "name"
     name high nationality weight
1    Ania   178      polish     67
2 Patrice   175      french     75
3   Julia    NA        <NA>     55
4     Jim    NA        <NA>     75

full_join(df1,df2) 

Full-join() will return columns of df1 and df2 containing all observations present in df1 and df2.

Joining, by = "name"
     name high nationality weight
1    Ania   178      polish     67
2   Marek   190      polish     NA
3   Kamil   175      polish     NA
4  Joanna   168      polish     NA
5 Patrice   175      french     75
6   Julia    NA        <NA>     55
7     Jim    NA        <NA>     75

anti_join(df1,df2) 
Anti_join() excludes rows from df1 which are present in df2.

Joining, by = "name"
    name high nationality
1  Marek   190      polish
2  Kamil   175      polish
3 Joanna   168      polish

semi_join(df1,df2)

Semi_join() will match the rows.

Joining, by = "name"
     name high nationality
1    Ania   178      polish
2 Patrice   175      french

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