Error incorrect number of probabilities

[hkhan]

Hi,
I keep receiving this error when i use the sample():
*Error in sample.int(length(x), size,replace, prob) : *

• incorrect number of probabilities*

This is what I am doing:

prod <- sample(prod_table$key, no_of_recs, replace=T, prob=c(1, 2,3,4,5,6))
  unit <- sample(c(1,2), no_of_recs, replace=T, prob=c(10, 3))

Please let me know what I'm doing wrong.
Thanks!!

[gueyenono]

Does prod_table$key have 6 values? Also, your probabilities should sum up to 1.
If you share your data (or a sample) then we can help you get your desired result.

[nirgrahamuk]

@hkhan

prod_table$key

it depends on what this is.
is it a 6 long vector ?

[hkhan]

prod_table has four values :

prod_table <-
  data.frame(key=c("Washing Machine", "Frudge", "Vacuum Cleaner", "Microwave Oven"),
             price=c(200, 500, 400, 150),
             stringsAsFactors = TRUE)

[hkhan]

prod_table has four values :

 prod_table <-
 data.frame(key=c("Washing Machine", "Frudge", "Vacuum Cleaner", "Microwave Oven"),
             price=c(200, 500, 400, 150),
             stringsAsFactors = TRUE)

[/quote]

[nirgrahamuk]

@hkhan

prob=c(1, 2,3,4,5,6)

that being the case, what was your intention when you chose these values ?

[hkhan]

somewhere else i had six variables - i think i muddled it up here and thought it was referencing that. but now i have changed it to four and yet i still get the same error

[gueyenono]

@hkhan

 data.frame(key=c("Washing Machine", "Frudge", "Vacuum Cleaner", "Microwave Oven"),
             price=c(200, 500, 400, 150),
             stringsAsFactors = TRUE)

If that is the case, then your prob argument needs to contain 4 values: one probability for each value. Also make sure that they sum up to one. Here is an example:

prod_table <-  data.frame(key=c("Washing Machine", "Frudge", "Vacuum Cleaner", "Microwave Oven"),
                 price=c(200, 500, 400, 150),
                 stringsAsFactors = TRUE)

sample(prod_table$key, no_of_recs, replace=T, prob=c(0.2, 0.1, 0.4, 0.3))

[nirgrahamuk]

@hkhan

but now i have changed it to four and yet i still get the same error

no_of_recs <- 3

prod_table <-
  data.frame(key=c("Washing Machine", "Frudge", "Vacuum Cleaner", "Microwave Oven"),
             price=c(200, 500, 400, 150),
             stringsAsFactors = TRUE)

set.seed(42)
prod <- sample(prod_table$key, no_of_recs, replace=T, prob=c(1, 2,3,4)/10)
unit <- sample(c(1,2), no_of_recs, replace=T, prob=c(10, 3)/13)
prod
unit

I don't get any errors ...

>prod
1] Washing Machine Washing Machine Microwave Oven 
Levels: Frudge Microwave Oven Vacuum Cleaner Washing Machine
> unit
[1] 2 1 1

[hkhan]

yes, thank you- this works!

[hkhan]

yeah i wasn't getting it to add up to one, hence my issue. Thank you it now works!