R merge dataframes with different columns with order

Question

I have three large data frames below, and want to merge into one data frame with order.

df 1:
First Name  Last Name
John        Langham
Paul        McAuley
Steven      Hutchison
Sean        Hamilton
N           N

df2:
First Name  Wage    Location
John        500     HK
Paul        600     NY
Steven      1900    LDN
Sean        800     TL
N           N       N

df3:
Last Name   Time
Langham     8
McAuley     9
Hutchison   12
Hamilton    7
N           N

desired output:
First Name  Last Name   Wage    Location    Time
John        Langham     500     HK          8
Paul        McAuley     600     NY          9
Steven      Hutchison   1900    LDN         12
Sean        Hamilton    800     TL          7
N           N           N       N           N

I know how to merge df1 and df2 but df1+2 merges to df3 by second column changed the order in desired output, so I want to ask is there any recommendation? Thank you.

Possible duplicate of [Simultaneously merge multiple data.frames in a list](http://stackoverflow.com/questions/8091303/simultaneously-merge-multiple-data-frames-in-a-list) — Ronak Shah, Sep 20 '16 at 04:12
(disagree this is a duplicate, this q is about getting the final outcome of multiple merges in a certain order, not about how to achieve multiple merges, as in the linked question) — arvi1000, Sep 28 '16 at 21:12

score 2 · Accepted Answer · answered Sep 20 '16 at 04:00

If you are trying to preserve the order as it appears in df1, create a column to memorialize that order, then use it again to set the order of df3

# record order
df1$original_order <- 1:nrow(df1)

# then do your merges...
# ...

# then restore the df1 order to df3
df3 <- df3[order(df3$original_order),]

If you want you can then also get rid of that column:

df3$original_order <- NULL

R merge dataframes with different columns with order

1 Answers1