[R] Merging big data.frame

Jeff Newmiller jdnewmil at dcn.davis.CA.us
Wed Apr 17 08:43:03 CEST 2013

check out the sqldf package
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Sent from my phone. Please excuse my brevity.

avinash sahu <avinash.sahu at gmail.com> wrote:

>Hi all,
>I am trying to merge 2 big data.frame. The problem is merge is memory
>intensive so R is going out of memory error: cannot allocate vector of
>360.1 Mb. To overcome this, I am exploring option of using data.table
>package. But its not helping in term of memory as merge in data.table
>fast but not memory efficient. Similar error is coming.
>My inputs are
> V1 V2
>1  a i1
>2  a i2
>3  a i3
>4  a i4
>5  b i5
>6  c i6
>  V1 V2
>1  a  x
>2  b  x
>3  a  y
>4  c  z
>I want  merge(x=inp1, y=inp2, by.x="V1", by.y="V1")
>so the output
> V1 V2.x V2.y
>1   a   i1    x
>2   a   i1    y
>3   a   i2    x
>4   a   i2    y
>5   a   i3    x
>6   a   i3    y
>7   a   i4    x
>8   a   i4    y
>9   b   i5    x
>10  c   i6    z
>Is there a way to do this without using merge in data.table? or Is
>any other solution to do this in more efficient and less memory ?
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>R-help at r-project.org mailing list
>PLEASE do read the posting guide
>and provide commented, minimal, self-contained, reproducible code.

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