R help - May 2010 - Reading in and writing out one line at a time

I hope that somebody can help me with this - I think very simple - issue...?

I am running a package that only accepts one line at a time, but I would
like to run this package on a dataframe of >500 lines. 

Dataframe "d" is a single column:

APPLES
PEARS
AUBERGINES
KUMQUATS

I would like to read one line of my dataframe "d", individually into a
new
frame "f", then execute the program on "f" and it provides
an output:
>mash(f)
[[1]]
[1]  FREDBLOGGS

[2]  250

I would like to record this output to a two column dataframe, "r",
such as:

FREDBLOGGS     250

and then repeat the process on the next line of dataframe "d", and so
on to
the end of dataframe "d",writing each line into "r" so that
the dataframe
"r" eventually reads:

FREDBLOGGS     250
JAMESJONES      175
TERRYTAITE       892
HARRYSMITH     320


I'm afraid that I'm new to this, but think that this first step in will
be
very useful in general. Thank you kindly for any help.
-- 
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Sent from the R help mailing list archive at Nabble.com.

On 20.05.2010 00:47, sedm1000 wrote:
>
> I hope that somebody can help me with this - I think very simple -
issue...?
>
> I am running a package that only accepts one line at a time, but I would
> like to run this package on a dataframe of>500 lines.
>
> Dataframe "d" is a single column:
>
> APPLES
> PEARS
> AUBERGINES
> KUMQUATS
>
> I would like to read one line of my dataframe "d", individually
into a new
> frame "f", then execute the program on "f" and it
provides an output:
>
>> mash(f)
>
> [[1]]
> [1]  FREDBLOGGS
>
> [2]  250
>
> I would like to record this output to a two column dataframe,
"r", such as:
>
> FREDBLOGGS     250
>
> and then repeat the process on the next line of dataframe "d",
and so on to
> the end of dataframe "d",writing each line into "r" so
that the dataframe
> "r" eventually reads:
>
> FREDBLOGGS     250
> JAMESJONES      175
> TERRYTAITE       892
> HARRYSMITH     320
>
>
> I'm afraid that I'm new to this, but think that this first step in
will be
> very useful in general. Thank you kindly for any help.

This will be slow, therefore I'd suggest to read the whole data frame at 
once and then feed it row by row into your function.

Uwe Ligges

Perhaps you mean something like sapply or apply?

When d is indeed a data.frame with one column: sapply(d[,1], mash)

Regards,

Jan van der Laan



On Thu, May 20, 2010 at 12:47 AM, sedm1000 <gdoran at mit.edu>
wrote:
>
> I hope that somebody can help me with this - I think very simple -
issue...?
>
> I am running a package that only accepts one line at a time, but I would
> like to run this package on a dataframe of >500 lines.
>
> Dataframe "d" is a single column:
>
> APPLES
> PEARS
> AUBERGINES
> KUMQUATS
>
> I would like to read one line of my dataframe "d", individually
into a new
> frame "f", then execute the program on "f" and it
provides an output:
>
>>mash(f)
>
> [[1]]
> [1] ?FREDBLOGGS
>
> [2] ?250
>
> I would like to record this output to a two column dataframe,
"r", such as:
>
> FREDBLOGGS ? ? 250
>
> and then repeat the process on the next line of dataframe "d",
and so on to
> the end of dataframe "d",writing each line into "r" so
that the dataframe
> "r" eventually reads:
>
> FREDBLOGGS ? ? 250
> JAMESJONES ? ? ?175
> TERRYTAITE ? ? ? 892
> HARRYSMITH ? ? 320
>
>
> I'm afraid that I'm new to this, but think that this first step in
will be
> very useful in general. Thank you kindly for any help.
> --
> View this message in context:
http://r.789695.n4.nabble.com/Reading-in-and-writing-out-one-line-at-a-time-tp2223726p2223726.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
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