title: Subset rows based on a specific threshold value
body: <p>I want to get a subset of the columns observations of my data frame, based on a threshold. I'll explain you the question with a little more details.</p>
  
  <p>I have a data frame with the methylation level of 35 patients afected by lung adenocarcinoma. This is a subset of my data:</p>
  
  <pre><code>&gt; df.met[1:5,1:5]
                  A2BP1       A2M     A2ML1     A4GALT       AAAS
  paciente6  0.36184475 0.4555788 0.6422624 0.08051388 0.15013343
  paciente7  0.47566878 0.7329827 0.4938048 0.45487573 0.10827520
  paciente8  0.17455497 0.7528387 0.5686839 0.37018038 0.12423923
  paciente9  0.04830471 0.5166676 0.8878207 0.08881092 0.11779075
  paciente10 0.16757806 0.7896194 0.5408747 0.35315243 0.09234602
  </code></pre>
  
  <p>Now, I need to get another object (with the same number of columns, but smaller number of rows, and diferent in every column) with a subset of the values greater than 0.1 for all the columns of the initial data frame.</p>
  
  <p>My intention is to obtain a object like this one (I don't know if is possible...):</p>
  
  <pre><code>            A2BP1       A2M     A2ML1     A4GALT       AAAS
  paciente6  0.36184475 0.4555788 0.6422624            0.15013343
  paciente7  0.47566878 0.7329827 0.4938048 0.45487573 0.10827520
  paciente8  0.17455497 0.7528387 0.5686839 0.37018038 0.12423923
  paciente9             0.5166676 0.8878207            0.11779075
  paciente10 0.16757806 0.7896194 0.5408747 0.35315243 
  </code></pre>
  
  <p>In other words, I want to avoid of my data frame, the values smaller than 0.1.</p>
  
  <p>Thank you so much! </p>