title: How to use filter like if then else statement on a list?
body: <p>i would like to add 1 items to a list which has only one item and add items(after using toInt to convert to integer) in a list y if number of items greater than 1 and the last items are the same</p>
  
  <p>How to do?</p>
  
  <pre><code>import Data.List.Split
  
  z = splitOn "+" "x^2+2*x^3+x^2"
  
  y = map (splitOn "*") z
  
  x = map head y
  
  toInt :: [String] -&gt; [Int]
  toInt = map read
  
  u = filter ((map length y)&gt;1) y
  
  Couldn't match expected type `a0 -&gt; Bool' with actual type `Bool'
  In the first argument of `filter', namely `((map length y) &gt; 1)'
  In the expression: filter ((map length y) &gt; 1) y
  In an equation for `u': u = filter ((map length y) &gt; 1) y
  </code></pre>
  
  <p>Failed, modules loaded: none.</p>