title: How to remove values in a Groovy map
body: <p>Say I have this map</p>
  
  <pre><code>def map = [:]
  map.put("us-east-1", ["vol-66c16ec2", "vol-654ce2c1", "vol-01234567"])
  map.put("us-east-2", ["vol-12345678", "vol-87654321", "vol-abcdefgh"])
  </code></pre>
  
  <p>which results in...</p>
  
  <pre><code>{
    "us-east-1" : [
      "vol-66c16ec2", "vol-654ce2c1", "vol-01234567"
    ],
    "us-east-2" : [
      "vol-12345678", "vol-87654321", "vol-abcdefgh"
    ]
  }
  </code></pre>
  
  <p>How can I iterate through the map so when value = "vol-abcdefgh" I want to remove that entry. So pseudo-code is...</p>
  
  <pre><code>for (it=iterate_through_map) {
    if (it == "vol-abcdefgh") {
       remove_entry(it)
    }
  }
  </code></pre>
  
  <p>and the resulting map is now...</p>
  
  <pre><code>{
    "us-east-1" : [
      "vol-66c16ec2", "vol-654ce2c1", "vol-01234567"
    ],
    "us-east-2" : [
      "vol-12345678", "vol-87654321"
    ]
  }
  </code></pre>