title: Read a zipped .csv file in R
body: <p>I have been trying hard to solve this, but I cannot get my head around how to read zipped .csv files in R. I could first unzip the files and then read them, but since the amount of unzipped data is around 22GB, I guess it is more practical to handle zipped files.</p>
  
  <p>I basically have many .csv files, which I ZIPPED ONE BY ONE into single .7z files. Every file is named like: <code>file1.csv</code>, <code>file2.csv</code>, etc., which zipped became respectively: <code>file1.csv.7z</code>, <code>file2.csv.7z</code>, etc.</p>
  
  <p>If I use the following command:</p>
  
  <pre><code>data &lt;- read.table(unz("substn-20100101.csv.7z", "substn-20100101.csv"), nrows=10, header=T, quote="\"", sep=",")
  </code></pre>
  
  <p>I get the message: </p>
  
  <pre><code>Error in open.connection(file, "rt") : cannot open the connection
  In addition: Warning message:
  In open.connection(file, "rt") : cannot open zip file 'substn-20100101.7z'
  </code></pre>
  
  <p>Any help would be much appreciated, thank you in advance.</p>