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10 October, 2023

R - In a for loop iterating through columns df[[i]] if a data frame, how do I print the name of column df[[i]] for each loop?

I'm trying to use a for-loop to iterate through the columns of a data frame, and for each loop print out the name of the column on each loop before the operation is performed (namely checking if there are missing values for that column).


I have tried all I can think of, but haven't had any luck so far.


This was my best guess, but it just returns NULL for the column name (I'm guessing because once I've extracted the data of the column it's already a nameless vector?).
for (i in seq_along(df)) {
# Print column name
print(colnames(df[[i]]))
# Print sum of missing values for each column
print(sum(is.na(df[[i]])))
# Print NA value rows
}



Output is as follows:
NULL
[1] 70
NULL
[1] 0
NULL
[1] 0
NULL
[1] 0
NULL



What can I do to print the column name for each pass?

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