title: Convert numeric values into binary (0/1)
body: <p>I have a data frame  with counts of different kinds of fruits of different people. Like below</p>
  <pre><code>    apple  banana  orange
  Tim     3       0       2
  Tom     0       1       1
  Bob     1       2       2
  </code></pre>
  <p>How can I change it into a binary matrix, i.e. if a person has at least one fruit, no matter how many he has, then the I record 1, if not, record 0. Like below</p>
  <pre><code>    apple  banana  orange
  Tim     1       0       1
  Tom     0       1       1
  Bob     1       1       1
  </code></pre>