1 Goal

The goal of this tutorial is to split a string in different characters and keep only the first element

2 Data import

library(purrr)

# In this tutorial we are going to use the mtcars dataset
data(mtcars)

3 Splitting the string

# We are going to take the names of the rows to find the brand of the car
brandcar <- rownames(mtcars)
head(brandcar)
## [1] "Mazda RX4"         "Mazda RX4 Wag"     "Datsun 710"       
## [4] "Hornet 4 Drive"    "Hornet Sportabout" "Valiant"
# We are going to use the strsplit function
# However as every model has different number of words the output is a list
head(strsplit(brandcar, split = " "))
## [[1]]
## [1] "Mazda" "RX4"  
## 
## [[2]]
## [1] "Mazda" "RX4"   "Wag"  
## 
## [[3]]
## [1] "Datsun" "710"   
## 
## [[4]]
## [1] "Hornet" "4"      "Drive" 
## 
## [[5]]
## [1] "Hornet"     "Sportabout"
## 
## [[6]]
## [1] "Valiant"
# Now we are going to select only the first element of each list
# We will use the function map from purrr
head(map(strsplit(brandcar, split = " "), 1))
## [[1]]
## [1] "Mazda"
## 
## [[2]]
## [1] "Mazda"
## 
## [[3]]
## [1] "Datsun"
## 
## [[4]]
## [1] "Hornet"
## 
## [[5]]
## [1] "Hornet"
## 
## [[6]]
## [1] "Valiant"
# Now we can transform into a character vector because we have 1 element per car
head(as.character(map(strsplit(brandcar, split = " "), 1)))
## [1] "Mazda"   "Mazda"   "Datsun"  "Hornet"  "Hornet"  "Valiant"

4 Summary

# In short we can define a string vector and do the whole process in two lines
brandcar <- rownames(mtcars)
mtcars$Brand <- as.character(map(strsplit(brandcar, split = " "), 1))
table(mtcars$Brand)
## 
##      AMC Cadillac   Camaro Chrysler   Datsun    Dodge   Duster  Ferrari 
##        1        1        1        1        1        1        1        1 
##     Fiat     Ford    Honda   Hornet  Lincoln    Lotus Maserati    Mazda 
##        2        1        1        2        1        1        1        2 
##     Merc  Pontiac  Porsche   Toyota  Valiant    Volvo 
##        7        1        1        2        1        1

5 Conclusion

In this tutorial we have learnt how to split a string into different words and select only the first one.