title: What is the name for a partially applied map
body: <p>In functional programming most common patterns tend to be given names that help differentiate them.</p>
  
  <p>I am trying to find what the name for a type of function that I would describe as a <em>partially applied map</em>. </p>
  
  <p>An example in Python:</p>
  
  <pre><code>from functools import partial
  seq_len = partial(map, len)
  seq_len(['alpha', 'beta', 'charlie'])
  </code></pre>
  
  <p>I understand these could also be described as functions that take sequences as input.</p>
  
  <p>Some functions that I identified as being interesting subjects of such partial application are:</p>
  
  <ul>
  <li>map</li>
  <li>reduce</li>
  <li>filter</li>
  </ul>
  
  <p>More:</p>
  
  <ul>
  <li>Python uses the "iterator" name to refer to objects that implement the iterator protocol. But in itertools functions that take sequences and return sequences are also referred to as "iterators"(<a href="https://docs.python.org/3.7/library/itertools.html" rel="nofollow noreferrer">https://docs.python.org/3.7/library/itertools.html</a>).</li>
  <li>JavaScript uses identical definition for iterator(<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Iterators_and_Generators" rel="nofollow noreferrer">https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Iterators_and_Generators</a>).</li>
  <li>Rust uses the term "consuming adaptors" for methods that <em>consume</em> the iterator and "iterator adaptors" for methods that transform the input iterator into a different iterator on output.</li>
  </ul>