title: R strsplit function in a data frame
body: <p>I create a data frame which now I want to separate one new column by split the ":" in first column.</p>
  
  <pre><code>data frame:
  unc.edu.0057f9f7-779b-4914-8290-abbad2a0d81e.2556919.rsem.genes.normalized_results:ASL|435  214.4421
  unc.edu.0057f9f7-779b-4914-8290-abbad2a0d81e.2556919.rsem.genes.normalized_results:ASS1|445 2863.8055
  unc.edu.0057f9f7-779b-4914-8290-abbad2a0d81e.2556919.rsem.genes.normalized_results:OTC|5009 0
  unc.edu.050c2191-b96c-41e7-abdb-e52cbe82f268.2456235.rsem.genes.normalized_results:ASL|435  332.7522
  unc.edu.050c2191-b96c-41e7-abdb-e52cbe82f268.2456235.rsem.genes.normalized_results:ASS1|445 3322.629
  unc.edu.050c2191-b96c-41e7-abdb-e52cbe82f268.2456235.rsem.genes.normalized_results:OTC|5009 0
  
  desired output:
  unc.edu.0057f9f7-779b-4914-8290-abbad2a0d81e.2556919.rsem.genes.normalized_results  ASL|435 214.4421
  unc.edu.0057f9f7-779b-4914-8290-abbad2a0d81e.2556919.rsem.genes.normalized_results  ASS1|445    2863.8055
  unc.edu.0057f9f7-779b-4914-8290-abbad2a0d81e.2556919.rsem.genes.normalized_results  OTC|5009    0
  unc.edu.050c2191-b96c-41e7-abdb-e52cbe82f268.2456235.rsem.genes.normalized_results  ASL|435 332.7522
  unc.edu.050c2191-b96c-41e7-abdb-e52cbe82f268.2456235.rsem.genes.normalized_results  ASS1|445    3322.629
  unc.edu.050c2191-b96c-41e7-abdb-e52cbe82f268.2456235.rsem.genes.normalized_results  OTC|5009    0
  </code></pre>
  
  <p>I have tried </p>
  
  <pre><code>strsplit(df$V1, split = "\\:")
  </code></pre>
  
  <p>but Error in strsplit(t$V1, split = "\:") : non-character argument come out. Thank you. </p>