2 question:
1.
I want to find max and min of date in "InvoiceDate" Column:
range(data$InvoiceDate)
and i get an error:
Error in Summary.factor(c(6839L, 6839L, 6839L, 6839L, 6839L, 6839L, 6839L, :
‘range’ not meaningful for factors
2.
when i use below function it returns nothing
data<-subset(data,InvoiceDate>= "2010-12-09")
this is error:
Warning message:
In Ops.factor(InvoiceDate, "2010-12-09") : ‘>=’ not meaningful for factors