title: How to select specific columns from lots of dataframes in r
body: <p>I am handling 303 data frames and each data frame has different name as well as contains different columns. What I want is that select specific columns of which name contain "_CD" and "_NM" from those lots of data frames. Is there any good way to deal with it?</p>
  
  <p>Note, those data frames were not listed. </p>
  
  <p>Here is an example (I cannot bring up the real data but show you the fake with similar format)</p>
  
  <p>table 1 name: AD_ITEM_CNT;</p>
  
  <ul>
  <li>columns : CKND_CLSF_CD, SUBJ_CD, ITEM_CNT, UPDT_DT</li>
  </ul>
  
  <p>table 2 name : BLAD_PE_XEXM</p>
  
  <ul>
  <li>columns : PT_SBST_NO, CEXM_NM, CEXM_CD, CEXM_RST, CEX_RSLT_CMNT, LDNG_DT</li>
  </ul>
  
  <p>table 3 name : BLAD_MR_HLTH</p>
  
  <ul>
  <li>columns : PT_SBST_NO, RGST_DT, EDU_DGRE_CD, DRNK_YN, JOB_KIND_CD ...</li>
  </ul>
  
  <p>The goal of this process is to create a table like the below</p>
  
  <pre><code>Table          |       column |  CD 
  -----------------------------------
  AD_ITEM_CNT    | CKND_CLSF_CD |  01
  AD_ITEM_CNT    | CKND_CLSF_CD |  02
  AD_ITEM_CNT    | CKND_CLSF_CD |  03
  AD_ITEM_CNT    | CKND_CLSF_CD |  04
  BLAD_PE_XEXM   | CEXM_CD      |  AVS
  BLAD_PE_XEXM   | CEXM_CD      |  ABE
  BLAD_PE_XEXM   | CEXM_CD      |  CVS
  BLAD_PE_XEXM   | CEXM_CD      |  UVS
  </code></pre>