'Multiply numeric columns of two different dataframes based on matching of other columns
I have the first dataframe like:
df1<-structure(list(`Demand Per Section` = c(80, 125, 350, 100, 538,
75, 25, 138, 138, 75, 150, 37, 225, 35, 40, 125, 25, 25, 125,
50), `Element Name` = c("Naphthalene", "Nitric acid (concentrated)",
"Sulphuric acid(concentrated)", "2-hydroxybenzoic acid", "Acetic anhydride",
"2-Naphthol", "Sodium Hydroxide", "Phenyl hydrazine hydrochloride",
"Glucose", "Sodium acetate", "Aniline", "Zinc poweder", "2-amino-benzoic acid",
"1.3-dihydroxybenzene", "Ethyl acetate", "hydroxy benzene", "phenyl methanol",
"Sodium carbonate", "Potassium permanganate", "Sodium bisulfite."
), `Course Name` = c("Course 1", "Course 1", "Course 1", "Course 1",
"Course 1", "Course 1", "Course 1", "Course 1", "Course 1", "Course 1",
"Course 1", "Course 1", "Course 1", "Course 1", "Course 1", "Course 1",
"Course 1", "Course 1", "Course 1", "Course 1"), Department = c("Chemsitry",
"Chemsitry", "Chemsitry", "Chemsitry", "Chemsitry", "Chemsitry",
"Chemsitry", "Chemsitry", "Chemsitry", "Chemsitry", "Chemsitry",
"Chemsitry", "Chemsitry", "Chemsitry", "Chemsitry", "Chemsitry",
"Chemsitry", "Chemsitry", "Chemsitry", "Chemsitry")), row.names = c(NA,
-20L), class = c("tbl_df", "tbl", "data.frame"), na.action = structure(c(`81` = 81L,
`101` = 101L, `127` = 127L, `134` = 134L, `135` = 135L, `136` = 136L,
`174` = 174L, `183` = 183L, `220` = 220L, `225` = 225L, `245` = 245L,
`286` = 286L, `288` = 288L, `290` = 290L, `305` = 305L, `314` = 314L,
`324` = 324L, `329` = 329L), class = "omit"))
`Demand Per Section` `Element Name` `Course Name` Department
<dbl> <chr> <chr> <chr>
1 80 Naphthalene Course 1 Chemsitry
2 125 Nitric acid (concentrated) Course 1 Chemsitry
3 350 Sulphuric acid(concentrated) Course 1 Chemsitry
4 100 2-hydroxybenzoic acid Course 1 Chemsitry
5 538 Acetic anhydride Course 1 Chemsitry
6 75 2-Naphthol Course 1 Chemsitry
7 25 Sodium Hydroxide Course 1 Chemsitry
8 138 Phenyl hydrazine hydrochloride Course 1 Chemsitry
9 138 Glucose Course 1 Chemsitry
10 75 Sodium acetate Course 1 Chemsitry
11 150 Aniline Course 1 Chemsitry
12 37 Zinc poweder Course 1 Chemsitry
13 225 2-amino-benzoic acid Course 1 Chemsitry
14 35 1.3-dihydroxybenzene Course 1 Chemsitry
15 40 Ethyl acetate Course 1 Chemsitry
16 125 hydroxy benzene Course 1 Chemsitry
17 25 phenyl methanol Course 1 Chemsitry
18 25 Sodium carbonate Course 1 Chemsitry
and a second dataframe like:
df2<-structure(list(`Course name` = c("Course 1", "Course 2", "Course 3",
"Course 4", "Course 1", "Course 2", "Course 3", "Course 4", "Course 5",
"Course 1", "Course 2", "Course 3", "Course 4", "Course 5"),
`number of sections` = c(3, 5, 3, 4, 7, 2, 7, 10, 3, 4, 5,
6, 2, 2), Department = c("Chemsitry", "Chemsitry", "Chemsitry",
"Chemsitry", "Biology", "Biology", "Biology", "Biology",
"Biology", "Physics", "Physics", "Physics", "Physics", "Physics"
)), row.names = c(NA, -14L), class = c("tbl_df", "tbl", "data.frame"
))
`Course name` `number of sections` Department
<chr> <dbl> <chr>
1 Course 1 3 Chemsitry
2 Course 2 5 Chemsitry
3 Course 3 3 Chemsitry
4 Course 4 4 Chemsitry
5 Course 1 7 Biology
6 Course 2 2 Biology
7 Course 3 7 Biology
8 Course 4 10 Biology
9 Course 5 3 Biology
10 Course 1 4 Physics
11 Course 2 5 Physics
12 Course 3 6 Physics
13 Course 4 2 Physics
14 Course 5 2 Physics
What I want is to create a new column in df1 named DemandCourse which will look into df2 in the columns of Course Name and Department and when both will match with Course Name and Department of df1 it will multiply the Demand per Section of df1 with the number of sections of df2. So for example the first row of the new column will be 80*3 =240
Sources
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Source: Stack Overflow
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