Joining Transnational Tables in R

Asked Nov 13 '18 at 18:37

Active Nov 13 '18 at 18:53

Viewed 22 times

I have two data tables MP and MK as shown below. I tried merging but I am getting wrong results! I know it can be done with a couple of for loops, but I am looking for some elegant way in data table for this, as the actual data table I have is huge(~100,000 rows) Can someone please help me join these two data tables to get the final result as shown below.

MP <- data.table(
  M = c("m1","m1","m1","m2","m2", "m1"),
  P = c("p1","p2","p4","p1","p3", "p1")
)

MK <- data.table(
  M = c("m1","m1","m2"),
  K = c("k1","k2","k1")
)

FINAL EXPECTED RESULT
M   P   K
m1  p1  k1
m1  p1  k2
m1  p2  k1
m1  p2  k2
m1  p4  k1
m1  p4  k2
m2  p1  k1
m2  p3  k1

edited Nov 13 '18 at 18:53

asked Nov 13 '18 at 18:37

Aman J

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`merge(MP, MK, by = 'M')` – IceCreamToucan Nov 13 '18 at 18:42
Awesome! Thank you. :) – Aman J Nov 13 '18 at 18:43
@IceCreamToucan I realized, my data had duplicate rows. I tried the solution and I am getting error. I have edited the question. I realize removing duplicates is the way to solve it. Am I right? or there is some way of not removing duplicates and still get the result? – Aman J Nov 13 '18 at 18:54
1

Removing duplicates is good practice. (Unless you want to keep them. They don't show up in the result you post, so apparently you don't want them.) – Gregor Thomas Nov 13 '18 at 18:59
Thanks, @Gregor. (: – Aman J Nov 13 '18 at 19:03

Joining Transnational Tables in R

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