Bringing in strings for parts of a formula.

[jbh1128d1]

I'm trying to productionize the `segmented` package in `r` so that multiple people can use it through `alteryx`. I bring in the strings

the_data_seg_z <-   "seg.z =" 
seg_data_first_part <-
c(credit_tier_bucket+insured_age_bucket+vehicle_length_bucket+rba_bucket)

and create a formula using

seg_formula <- as.formula(paste(the_data_seg_z, seg_data_first_part, sep = "
~ "))

That seems to run without error. I also bring in a string for the psi as

seg_data_psi <- c(credit_tier_bucket= c(3), insured_age_bucket= c(33),
vehicle_length_bucket= c(28), rba_bucket= c(3000, 18000))

my final line of code is:

piecewise_control <- seg.control(n.boot = 0)
piecewise_seg2 <- segmented(piecewise2, seg_formula, psi =
list(seg_data_psi), control = piecewise_control)

I then get an error that states `wrong number of terms in seg.Z or psi` but the terms match each other.

I feel like it's not reading the "psi" string correctly but I'm not sure the best way to bring it in.

[SydneyF]

Hi @jbh1128d1,

Does this code function as expected in R Studio? Are you importing the segmented package in R code in your R tool? Can you please include a screenshot of your messages, and your complete code? I would be happy to try troubleshooting this with you.

Thanks!

[jbh1128d1 · Accepted solution]

Hi @SydneyF.  Thank you for replying.  I just got the answer after asking the same 'type' of question in regards to @Dr.Dan's r-based macro series on there.  It does function in RStudio and the segmented packages is installed and loaded during the r-tool process.  The problem is r was evaluating this a string.  I needed to use the 'eval(parse(text = paste0" command to get R to read correctly. 

OLD CODE: 

the_data_seg_z <-   "seg.z =" 
seg_data_first_part <-
c(credit_tier_bucket+insured_age_bucket+vehicle_length_bucket+rba_bucket)

and create a formula using

seg_formula <- as.formula(paste(the_data_seg_z, seg_data_first_part, sep = "
~ "))

That seems to run without error. I also bring in a string for the psi as

seg_data_psi <- c(credit_tier_bucket= c(3), insured_age_bucket= c(33),
vehicle_length_bucket= c(28), rba_bucket= c(3000, 18000))

my final line of code is:

piecewise_control <- seg.control(n.boot = 0)
piecewise_seg2 <- segmented(piecewise2, seg_formula, psi =
list(seg_data_psi), control = piecewise_control)

NEW CODE:

seg_data <- read.Alteryx("#3", mode="data.frame")
seg_data_seg_z <- seg_data$piecewise_formula_seg_z
seg_data_first_part <- seg_data$piecewise_formula_first_part
seg_data_psi <- seg_data$piecewise_formula_psi
seg_formula <- paste(seg_data_seg_z, seg_data_first_part, sep = " ~ ")
seg_formula2 <- paste(seg_data_psi)
#Get bootstrap folds?
boot <- '%Question.How many bootstrap folds?%'
piecewise_control <- seg.control(n.boot = 0)
#run segmented formula
piecewise_seg2 <- eval(parse(text = paste0("segmented(piecewise2, ",seg_formula,", ",seg_data_psi,"),control = piecewise_control)")))