v class="odoc-spec"><div class="spec value" id="val-fold_mapi" class="anchored"><a href="#val-fold_mapi" class="anchor"></a><code><span><span class="keyword">val</span> fold_mapi : 
  <span><a href="#type-t">t</a> <span class="arrow">&#45;&gt;</span></span>
  <span>init:<span class="type-var">'a</span> <span class="arrow">&#45;&gt;</span></span>
  <span>f:<span>( <span><a href="#type-key">key</a> <span class="arrow">&#45;&gt;</span></span> <span><span class="type-var">'a</span> <span class="arrow">&#45;&gt;