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Create intervention objects from Rx input

Source: R/class_rx.R
ev_rx.Rd

See details below for Rx specification. Actual parsing is done by parse_rx(); this function can be used to debug Rx inputs.

Usage

ev_rx(x, y, ...)

# S4 method for class 'mrgmod,character'
ev_rx(x, y, ...)

# S4 method for class 'character,missing'
ev_rx(x, df = FALSE, ...)

parse_rx(x)

Arguments

x

a model object or character Rx input.

y

character Rx input; see details.

...

not used at this time.

df

if TRUE then a data frame is returned.

Value

The method dispatched on model object (mrgmod) returns another model object. The character method returns an event object. The parse_rx function return a list named with arguments for the event object constructor ev().

Rx specification

  • The dose is found at the start of the string by sequential digits; this may be integer, decimal, or specified in scientific notation

  • Use in to identify the dosing compartment number; must be integer

  • Use q to identify the dosing interval; must be integer or decimal number (but not scientific notation)

  • Use over to indicate an infusion and its duration; integer or decimal number

  • Use x to indicate total number of doses; must be integer

  • Use then or , to separate dosing periods

  • Use after to insert a lag in the start of a period; integer or decimal number (but not scientific notation)

  • Use & to implement multiple doses at the same time

Examples

# example("ev_rx")

ev_rx("100")
#> Events:
#>   time amt cmt evid
#> 1    0 100   1    1

ev_rx("100 in 2")
#> Events:
#>   time amt cmt evid
#> 1    0 100   2    1

ev_rx("100 q12 x 3")
#> Events:
#>   time amt ii addl cmt evid
#> 1    0 100 12    2   1    1

ev_rx("100 over 2")
#> Events:
#>   time amt rate cmt evid
#> 1    0 100   50   1    1

ev_rx("100 q 24 x 3 then 50 q12 x 2")
#> Events:
#>   time amt ii addl cmt evid
#> 1    0 100 24    2   1    1
#> 2   72  50 12    1   1    1

ev_rx("100 then 50 q 24 after 12")
#> Events:
#>   time amt ii addl cmt evid
#> 1    0 100  0    0   1    1
#> 2   12  50 24    0   1    1

ev_rx("100.2E-2 q4")
#> Events:
#>   time   amt ii cmt evid
#> 1    0 1.002  4   1    1

ev_rx("100 over 2.23")
#> Events:
#>   time amt     rate cmt evid
#> 1    0 100 44.84305   1    1

ev_rx("100 q 12 x 3")
#> Events:
#>   time amt ii addl cmt evid
#> 1    0 100 12    2   1    1

ev_rx("100 in 1 & 200 in 2") 
#> Events:
#>   time amt cmt evid
#> 1    0 100   1    1
#> 2    0 200   2    1

parse_rx("100 mg q 24 then 200 mg q12")
#> [[1]]
#> [[1]]$time
#> [1] 0
#> 
#> [[1]]$cmt
#> [1] 1
#> 
#> [[1]]$amt
#> [1] 100
#> 
#> [[1]]$ii
#> [1] 24
#> 
#> 
#> [[2]]
#> [[2]]$time
#> [1] 0
#> 
#> [[2]]$cmt
#> [1] 1
#> 
#> [[2]]$amt
#> [1] 200
#> 
#> [[2]]$ii
#> [1] 12
#> 
#>