title: Combine different values of multiple columns into one column
body: <p>Need help to &quot;translate&quot; a python example to rust. The python example was given <a href="https://stackoverflow.com/questions/69890056/combine-different-values-of-multiple-columns-into-one-column-in-polars">here</a></p>
  <p>Here is the code snippet I try to make work:</p>
  <pre><code>use polars::prelude::*;
  
  fn main() {
      let s1 = Series::new(&quot;Fruit&quot;, &amp;[&quot;Apple&quot;, &quot;Apple&quot;, &quot;Pear&quot;]);
      let s2 = Series::new(&quot;Color&quot;, &amp;[&quot;Red&quot;, &quot;Yellow&quot;, &quot;Green&quot;]);
  
      let df = DataFrame::new(vec![s1, s2]).unwrap();
  
      let df_lazy = df.lazy();
  
      /*
  
      This is the PYTHON version I like to recreate in RUST:
  
      df_lazy.with_columns([
                      # string fmt over multiple expressions
                      pl.format(&quot;{} has {} color&quot;, &quot;Fruit&quot;, &quot;Color&quot;).alias(&quot;fruit_list&quot;),
                      # columnar lambda over multiple expressions
                      pl.map([&quot;Fruit&quot;, &quot;Color&quot;], lambda s: s[0] + &quot; has &quot; + s[1] + &quot; color&quot; ).alias(&quot;fruit_list2&quot;),
                      ])
       */
  
  }
  
  </code></pre>
  <p>I can't even get a simple select to work?! Now I am lost.</p>