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POCount the length (number of lines) of a CSV file?
 

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    <p>I have a form (Rails) which allows me to load a .csv file using the <code>file_field</code>. In the view: </p> <pre><code> &lt;% form_for(:upcsv, :html =&gt; {:multipart =&gt; true}) do |f| %&gt; &lt;table&gt; &lt;tr&gt; &lt;td&gt;&lt;%= f.label("File:") %&gt;&lt;/td&gt; &lt;td&gt;&lt;%= f.file_field(:filename) %&gt;&lt;/td&gt; &lt;/tr&gt; &lt;/table&gt; &lt;%= f.submit("Submit") %&gt; &lt;% end %&gt; </code></pre> <p>Clicking Submit redirects me to another page (create.html.erb). The file was loaded fine, and I was able to read the contents just fine in this second page. I am trying to show the number of lines in the .csv file in this second page. </p> <p>My controller (semi-pseudocode):</p> <pre><code>class UpcsvController &lt; ApplicationController def index end def create file = params[:upcsv][:filename] ... #params[:upcsv][:file_length] = file.length # Show number of lines in the file #params[:upcsv][:file_length] = file.size ... end end </code></pre> <p>Both <code>file.length</code> and <code>file.size</code> returns '91' when my file only contains 7 lines. From the Rails documentation that I read, once the Submit button is clicked, Rails creates a temp file of the uploaded file, and the <code>params[:upcsv][:filename]</code> contains the contents of the temp/uploaded file and not the <em>path</em> to the file. And I don't know how to extract the number of lines in my original file. What is the correct way to get the number of lines in the file? </p> <p>My create.html.erb:</p> <pre><code>&lt;table&gt; &lt;tr&gt; &lt;td&gt;File length:&lt;/td&gt; &lt;td&gt;&lt;%= params[:upcsv][:file_length] %&gt;&lt;/td&gt; &lt;/tr&gt; &lt;/table&gt; </code></pre> <p>I'm really new at Rails (just started last week), so please bear with my stupid questions. </p> <p>Thank you!</p> <p><strong>Update:</strong> apparently that number '91' is the number of individual characters (including carriage return) in my file. Each line in my file has 12 digits + 1 newline = 13. 91/13 = 7.</p>
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    1. USMathias
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    1. COBe real careful allowing a file to be uploaded without some tests on filesize. Imagine the problems if the file uses all the diskspace on your drive. Or, if the file is many gigabytes of carriage-returns, and your code in Rails is spinning trying to read and count the lines, DOSing your host. If you are on Linux you might want to have the OS's `wc` command do the lifting for you as it can return the line-count and number of characters in the file very quickly, without Rails having to open and read it.
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      1. USthe Tin Man
 

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