title: Change a value from a specific row to in a data frame in R
body: <p>I am currently tying to change some specific values from some specific rows in a data frame with dimensions (401, 2). </p>
  
  <p>The data frame looks like this:</p>
  
  <p><code>logFC        pval
  cg00035864  2.931898e-02 0.519802679
  cg00061679 -9.465129e-05 0.519802679
  cg00063477 -1.360574e-01 0.244373340
  cg00121626  7.946710e-03 0.611252125
  cg00212031 -6.052011e-02 0.774827599
  cg00213748 -9.248549e-02 0.851445095
  cg00214611  8.384351e-02 0.519802679
  cg00223952  2.184674e-03 0.998934883
  cg00243321  9.606841e-02 0.519802679
  cg00271873  1.781436e-01 0.605388199
  cg00272582  1.186292e-01 0.191905652
  cg00308367  1.496136e-02 0.791579139
  cg00311963  1.260400e-01 0.519802679
  cg00335297  1.819981e-01 0.405942400
  cg00455876  1.107911e-01 0.519802679
  cg00576139 -9.465129e-05 0.519802679
  cg00599377  9.778042e-02 0.519802679
  cg00639218  1.005280e-01 0.719199850
  cg00676506  2.603663e-02 0.706729687
  cg00679624 -3.499232e-02 0.735048055
  cg00762184  3.561985e-02 0.039468075
  cg00789540  1.296961e-01 0.519802679
  cg00876332 -1.240570e-01 0.991495608
  cg00975375  1.242095e-01 0.519802679
  cg01053349  6.237889e-02 0.938655973
  cg01061520  3.988364e-02 0.529964491
  cg01073572 -9.700589e-02 0.000829731
  cg01086462 -5.650370e-02 0.519802679
  cg01141334  1.130912e-01 0.883360324
  cg01209756  9.301333e-02 0.519802679</code></p>
  
  <p>What I would like is to change the values from those rows from the column logFC that don't pass a 5% FDR (column pval, which is already adjusted). </p>
  
  <p>I was doing this in a very rough way, just checking which one where not significant and then change them into 0. As the following way:</p>
  
  <p><code>data[data$pval &gt;= 0.05,]</code> </p>
  
  <ul>
  <li>Here I look which rows are the ones that I want to change. Let's put an example that are the rows 2,3,5,8,10 and 11 from the original data frame. Then I proceed like this:</li>
  </ul>
  
  <p><code>data$logFC[c(2,3,5,8,10,11)] &lt;- 0</code></p>
  
  <p>The current problem is that I used to do this in data frame that had a dimension 15, 2. Right now, as said before, the dimension is way larger (401, 2). So I can't do it "manually". </p>
  
  <p>Does somebody know an effective way to do this?</p>
  
  <p>Thank you very much,</p>
  
  <p>Aina</p>