title: How to get the changed content (string) after first loop iteration to be used in next iteration in Robot framework
body: <p>I have a list of strings where a specified part should be replaced with another.</p>
  <p>String_01:</p>
  <pre><code>UNH+000000'
  BGM+ZLI+000000'
  DTM+3:20210430:102'
  RFF+AFL:000000'
  RFF+CO:186577666'
  RFF+PK:000000'
  MOA+125:000000'
  MOA+150:000000'
  UNT+26+000000'
  </code></pre>
  <p>String_02:</p>
  <pre><code>UNH+000000'
  BGM+ZLI+000000'
  DTM+3:20210430:102'
  RFF+AFL:000000'
  RFF+CO:186578112'
  RFF+PK:000000'
  MOA+125:000000'
  MOA+150:000000'
  UNT+26+000000'
  </code></pre>
  <p>String_03:</p>
  <pre><code>UNH+000000'
  BGM+ZLI+000000'
  DTM+3:20210430:102'
  RFF+AFL:000000'
  RFF+CO:186601036'
  RFF+PK:000000'
  MOA+125:000000'
  MOA+150:000000'
  UNT+66+000000'
  </code></pre>
  <p>Then I have a dictionary key containing the things what should be replaced and value has the new value.</p>
  <pre><code>&amp;{PO_PAIRS}             186577666=4500000842    186578112=4500000843    186601036=4500000844
  </code></pre>
  <p>Now I iterate through every string with the dictionary. If the dictionary key is found from the string, it's changed to dictionary value.</p>
  <pre><code>NewString
      [Arguments]             ${string}
      FOR     ${key}      IN  @{PO_PAIRS}
          ${value} =             Get from dictionary     ${PO_PAIRS}        ${key}
          ${changed_string} =    Replace string          ${string}          ${key}  ${value}
      END
      [Return]                   ${changed_string}
  </code></pre>
  <p>The problem is that after first iteration of the loop, the <code>${changed_string}</code> should be the starting point for the next iteration instead of <code>${string}</code>. Is there some way to set the <code>${changed_string}</code> for the next iterations in the loop?</p>