R Error in merge – fix.by must specify uniquely valid column (2 Examples)
This article illustrates how to handle the “Error in fix.by(by.y, y) : ‘by’ must specify a uniquely valid column” in R programming.
Construction of Example Data
my_df1 <- data.frame(ID_a = 101:106, # Construct first example data a = 1:6) my_df1 # Show data in RStudio console # ID_a a # 1 101 1 # 2 102 2 # 3 103 3 # 4 104 4 # 5 105 5 # 6 106 6 |
my_df1 <- data.frame(ID_a = 101:106, # Construct first example data a = 1:6) my_df1 # Show data in RStudio console # ID_a a # 1 101 1 # 2 102 2 # 3 103 3 # 4 104 4 # 5 105 5 # 6 106 6
my_df2 <- data.frame(ID_b = 101:106, # Construct second example data b = LETTERS[1:6]) my_df2 # Show data in RStudio console # ID_b b # 1 101 A # 2 102 B # 3 103 C # 4 104 D # 5 105 E # 6 106 F |
my_df2 <- data.frame(ID_b = 101:106, # Construct second example data b = LETTERS[1:6]) my_df2 # Show data in RStudio console # ID_b b # 1 101 A # 2 102 B # 3 103 C # 4 104 D # 5 105 E # 6 106 F
Example 1: Replicating the Error in fix.by(by.y, y) : ‘by’ must specify a uniquely valid column
merge(my_df1, # merge() function leads to error my_df2, by.x = "ID_a") # Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column |
merge(my_df1, # merge() function leads to error my_df2, by.x = "ID_a") # Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column
Example 2: Solving the Error in fix.by(by.y, y) : ‘by’ must specify a uniquely valid column
merge(my_df1, # merge() function works fine my_df2, by.x = "ID_a", by.y = "ID_b") |
merge(my_df1, # merge() function works fine my_df2, by.x = "ID_a", by.y = "ID_b")
Related Articles & Further Resources
Have a look at the following list of R tutorials. They focus on topics such as merging and coding errors: