> class(df1$Date)
[1] "POSIXlt" "POSIXt"
> length(df1$Date)
[1] 116
> length(unlist(df1$Date))
[1] 1276
> length(unlist(sapply(df1, unlist)))
[1] 3016
> length(unlist(sapply(df1, as.character))) #ans
[1] 1856
> dim(df1) #ans
[1] 116 16
> 116*16 #ans
[1] 1856
> length(unlist(sapply(df1, as.character))) == prod(dim(df1)) #matched, resolved
[1] TRUE