How to add column to data frame using another data frame?

Question

I have two data frames as given below.

> df1 = data.frame(Letters1 = as.factor(rep(letters[1:3],c(4,3,5))), Numbers = 1:12)
> df1
   Letters1 Numbers
1         a       1
2         a       2
3         a       3
4         a       4
5         b       5
6         b       6
7         b       7
8         c       8
9         c       9
10        c      10
11        c      11
12        c      12
> df2 = data.frame(Letters2 = letters[1:3],Dates = as.Date(1:3, origin = "2016-07-31"))
> df2
  Letters2      Dates
1       a 2016-08-01
2       b 2016-08-02
3       c 2016-08-03

How to add Dates column from data frame 2 to data frame 1 for each character of Letters1 column?

`merge(df1, df2, by.x = "Letters1", by.y = "Letters2")` – Ronak Shah Aug 27 '16 at 05:20 — Ronak Shah, Aug 27 '16 at 05:20

score 1 · Accepted Answer · answered Aug 27 '16 at 05:20

1

Will this help?

df1$Dates <- df2$Dates[match(df1$Letters1, df2$Letters2)]

answered Aug 27 '16 at 05:20

Apricot

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How to add column to data frame using another data frame?

1 Answers1