[R] Reading multiple tables from one .txt doc

[William Dunlap]

The following base R code does roughly what Bert suggests.  It does
no checking that the data is in the format you describe.  The
split-by-cumsum
trick is a handy idiom.

# lines <- readLines(yourFile), or, for this example:
lines <- c("#One","X Y Z","1 2 3","4 5 6","",
                "#Two", "X Y Z", "11 12 13", "",
                "#Three", "X Y Z", "21 22 23")
tables <- split(lines, cumsum( grepl("^#", lines)))
names(tables) <- vapply(tables, function(table)sub("^#", "", table[1]), "")
lapply(tables, function(text)read.table(text=text, header=TRUE, skip=1))
#$One
#  X Y Z
#1 1 2 3
#2 4 5 6
#
#$Two
#   X  Y  Z
#1 11 12 13
#
#$Three
#   X  Y  Z
#1 21 22 23


Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Tue, May 3, 2016 at 8:41 AM, Bert Gunter <bgunter.4567 at gmail.com> wrote:

> One approach would be to use ?readLines to read the lines into a
> character vector. You could then use indexing to remove all the blank
> and header (lines beginning with "image") lines. You can now find the
> indices of where the separate data blocks begin (they all begin with
> "#", right?) and then sequentially read them into a list of data
> frames, using ?strsplit to delineate columns and ?as.numeric to
> convert the numeric columns. I leave it to you to work out what I
> think are the straightforward details.
>
> Do note, however, that there may be better ways to do this, especially
> using some of the text manipulation packages and functions.  Have a
> look at the "stringr" package or any others that searching might bring
> up (rseek.org is a good search site for R; as is google of course).
> And wait a bit for better suggestions before proceeding, as my brute
> force approach should probably be considered a last resort.
>
>
> Cheers,
> Bert
>
>
>
>
> Bert Gunter
>
> "The trouble with having an open mind is that people keep coming along
> and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>
>
> On Tue, May 3, 2016 at 7:45 AM, Mark Fingerle
> <mark.fingerle at brainlab.com> wrote:
> > Dear all,
> > I have a .txt file which contains multiple tables and I would like to
> read these tables separately in order to create graphs for each one.
> > The tables are separated by a blank line, have a variable number of
> lines, fixed nr. Of rows, have a header and a comment above the header (#)
> which contains a specific word that identifies each table. (see example
> below). It would be possible to change the layout of the .txt data a bit
> (Add a word, remove comment etc..)
> > I would be extremely grateful if anyone could help me with this daunting
> task :-)
> > Example:
> > # CoordA
> > Image    X             Y             Z             MeasuredMove
> MachineMove
> > vf_36.png            -114.345475       -89.043448         556.073402
>      0             0
> > vf_37.png            -111.118715       -89.978534         606.040764
>      50.080172           50.000000
> > vf_38.png            -107.911209       -90.901958         656.025557
>      50.096111           50.000000
> > vf_39.png            -104.693931       -91.814392         705.982620
>      50.068868           50.000000
> > vf_40.png            -101.459549       -92.730113         755.983835
>      50.114082           50.000000
> >
> > # CoordB
> > Image    X             Y             Z             MeasuredMove
> MachineMove
> > vf_36.png            -115.345475       -89.043448         556.073402
>      0             0
> > vf_37.png            -115.118715       -89.978534         606.040764
>      50.080172           50.000000
> > vf_38.png            -134.911209       -90.901958         656.025557
>      50.096111           50.000000
> > vf_39.png            -164.693931       -91.814392         705.982620
>      50.068868           50.000000
> > vf_40.png            -134.459549       -92.730113         755.983835
>      50.114082           50.000000
> >
> > # CoordC
> > Image    X             Y             Z             MeasuredMove
> MachineMove
> > vf_36.png            -168.345475       -89.043448         556.073402
>      0             0
> > vf_37.png            -115.118715       -89.978534         606.040764
>      50.080172           50.000000
> > vf_38.png            -146.911209       -90.901958         656.025557
>      50.096111           50.000000
> > vf_39.png            -187.693931       -91.814392         705.982620
>      50.068868           50.000000
> > vf_40.png            -185.459549       -92.730113         755.983835
>      50.114082           50.000000
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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