I am trying to extract information from an XML file from ClinicalTrials.gov. The file is organized in the following way:

```
<clinical_study>
  ...
  <brief_title>
  ...
  <location>
    <facility>
      <name>
      <address>
        <city>
        <state>
        <zip>
        <country>
    </facility>
    <status>
    <contact>
      <last_name>
      <phone>
      <email>
    </contact>
  </location>
  <location>
    ...
  </location>
  ...
</clinical_study>

```

I can use the R XML package from CRAN in the following code to extract all location nodes from the XML file:

```
library(XML)
clinicalTrialUrl <- "http://clinicaltrials.gov/ct2/show/NCT01480479?resultsxml=true"
xmlDoc <- xmlParse(clinicalTrialUrl, useInternalNode=TRUE)
locations <- xmlToDataFrame(getNodeSet(xmlDoc,"//location"))

```

This works kind of ok. **However**, if you look at the data frame, you will notice that the xmlToDataFrame function lumped together everything under `<facility>` into a single concatenated string. A solution would be to write code to generate the data frame column by column, for example, you could generate