Select Columns that Match Character String in R (Example Code)
In this article you’ll learn how to extract variables with a partial string match in the column name in R programming.
Construction of Exemplifying Data
data(iris) # Load example data head(iris) # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 2 4.9 3.0 1.4 0.2 setosa # 3 4.7 3.2 1.3 0.2 setosa # 4 4.6 3.1 1.5 0.2 setosa # 5 5.0 3.6 1.4 0.2 setosa # 6 5.4 3.9 1.7 0.4 setosa |
data(iris) # Load example data head(iris) # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 2 4.9 3.0 1.4 0.2 setosa # 3 4.7 3.2 1.3 0.2 setosa # 4 4.6 3.1 1.5 0.2 setosa # 5 5.0 3.6 1.4 0.2 setosa # 6 5.4 3.9 1.7 0.4 setosa
Example: Extract Variables that Contain Certain String in Column Name Using grep Function
data_Length <- iris[ , grep("Length", colnames(iris))] # Selecting string matches head(data_Length) # Display head of subset # Sepal.Length Petal.Length # 1 5.1 1.4 # 2 4.9 1.4 # 3 4.7 1.3 # 4 4.6 1.5 # 5 5.0 1.4 # 6 5.4 1.7 |
data_Length <- iris[ , grep("Length", colnames(iris))] # Selecting string matches head(data_Length) # Display head of subset # Sepal.Length Petal.Length # 1 5.1 1.4 # 2 4.9 1.4 # 3 4.7 1.3 # 4 4.6 1.5 # 5 5.0 1.4 # 6 5.4 1.7