title: Multiple regex extract from a text R
body: <p>I have the following df</p>
  
  <pre><code>df = data.frame(id = c(1,2,3), text = c('Label issues as ISS101  and ISS 201 on label 23 with x203 17','issue as ISS5051 with label 01 as l018','there is nothing here') 
  </code></pre>
  
  <p>I want to extract &amp; create the following data frame from the df</p>
  
  <pre><code>id  iss     label  ext1 ext2
   1  ISS101  23     x203  17
   1  ISS201  23     x203  17
   2  ISS5051 01     l018  NA
   3    NA    NA      NA   NA
  </code></pre>
  
  <p>The length of iss can vary as seen in the example. It may or may not have a space between "ISS" &amp; the subsequent digits, again this is visible in the e.g.
  The length of label, ext1 &amp; ext2 are fixed.
  I have tried various possibilities with regex using stringr &amp; dplyr. But none of these are close to the solution &amp; hence worth mentioning here. Looking forward for help, let me know if you need any more details.</p>