[R] Re constructing a dataframe from a database of newspaper articles

David Duffy David.Duffy at qimr.edu.au
Mon Jul 24 01:19:16 CEST 2006

> From: Bob Green <bgreen at dyson.brisnet.org.au>
> I am hoping for some assistance with formatting a large text file which
> consists of a series of individual records. Each record includes specific
> labels/field names (a sample of 1 record (one of the longest ones) is
> below  - at end of post. What I want to do is reformat the data, so that
> each individual record becomes a row (some cells will have a lot of text).
> For example, the column variables I want are (a) HD  in one column
> (b)    BY in one column (c) WC data in one column,  (d) PD data in one
> column, (e) SC data in one column (f) PG data in one column  & g) LP and TD
> text in one column  - this column can contain quite a lot of text, e.g 1900
> words. The other fields are unwanted
> If there were 150 individual records, when formatted this would be a 7
> column by 150 row dataset.

Most transparently,

txt <- readLines("c:\\cm-mht1.txt")
no_of_records <- length(grep("^HD",txt)
res <- matrix(nr=no_of_records, nc=8)
idx <- 0
for (i in 1:length(txt)) {
  if (regexpr("^HD", txt[i])!=-1) idx <- idx+1

  if (regexpr("^HD", txt[i])!=-1) res[idx, 1] <- txt[i]
  if (regexpr("^BY", txt[i])!=-1) res[idx, 2] <- txt[i]
  if (regexpr("^TD", txt[i])!=-1) res[idx, 8] <- txt[i]
res[,7] <- paste(res[,7], res[,8], sep="; ")
res <- res[,-8]

| David Duffy (MBBS PhD)                                         ,-_|\
| email: davidD at qimr.edu.au  ph: INT+61+7+3362-0217 fax: -0101  /     *
| Epidemiology Unit, Queensland Institute of Medical Research   \_,-._/
| 300 Herston Rd, Brisbane, Queensland 4029, Australia  GPG 4D0B994A v

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