The returned column names are from the source. So if you have lazy operations then the colnames here does not reflects the results of those operations. To obtain the correct names try names(collect(get_chunk(df, 1)))

colnames(x, ...)

# S3 method for disk.frame
names(x, ...)

# S3 method for disk.frame
colnames(x, ...)

# S3 method for default
colnames(x, ...)

Arguments

x

a disk.frame

...

not used