2019-07-12
r compare two data.tables by row
stackoverflow
Question

I have two data.tables that I want to compare.

But don't know why there is a warning

DT1 <- data.table(ID=c("F","A","E","B","C","D","C"),
                  num=c(59,3,108,11,22,54,241),
                  value=c(90,47,189,38,42,86,280),
                  Mark=c("Mary","Tom","Abner","Norman","Joanne",
                  "Bonnie","Trista"))

DT2 <- data.table(Mark=c("Mary","Abner","Bonnie","Trista","Norman"),
                  numA=c(48,20,88,237,20),
                  numB=c(60,326,54,268,89),
                  valueA=c(78,34,78,270,59),
                  valueB=c(90,190,90,385,75))

DToutput <- DT1[(num > DT2$numA & num < DT2$numB &
                value > DT2$valueA & value < DT2$valueB)]

My goal:

I want to find num and value based on Mark in DT1, and there is a range of numA and numB in DT2.

For example:

For row F in DT1, num = 59 and value = 90, and Mark = "Mary". So, when using by=Mary, you must also match:

num(59) > DT2$numA(48) & num(59) < DT2$numB(60) & value(90) > DT2$valueA(78) & value(90) < DT2$valueB(90)

You can see that 90 < 90 does not hold, so my result will not have row F

I got this warning:

Warning messages:
 1: In num > DT2$numA : longer object length is not a multiple of shorter object lengt
 2: In num < DT2$numB : longer object length is not a multiple of shorter object lengt
 3: In value > DT2$valueA : longer object length is not a multiple of shorter object lengt
 4: In value < DT2$valueB : longer object length is not a multiple of shorter object lengt

How can I modify it to complete what I want to do?

Thank you

Added: Multiple identical Marks may be used in DT2, but the values are not the same range. Does this affect the comparison?

Answer
1

Is this generally what you are looking for? I joined the datatables and filtered using between for your conditions. If this is not what you are looking for, can you post a datatable of your expected output?

library(data.table)

DT1[DT2, on = "Mark"][between(num, numA, numB, incbounds = F) & between(value, valueA, valueB, incbounds = F)]

   ID num value   Mark numA numB valueA valueB
1:  E 108   189  Abner   20  326     34    190
2:  C 241   280 Trista  237  268    270    385
r compare two data.tables by row
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