title: Convert multiple datatype to float?
body: <p>Using pandas, how to convert multiple dateframe column of datatype "object" to float.</p>
  
  <pre><code>df = pd.DataFrame()
  df["A"] = ["123.45","34","-9","4","5"]
  df["B"] = ["-9.07","5.4","3","1.0","4.5557"]
  df["C"] = ["34","34.98","-9.654","45","6"]
  df["D"] = ["AAA","AVF","ERD","DFE","SFE"]
  </code></pre>
  
  <p>using this gives AttributeError: 'list' object has no attribute 'apply': </p>
  
  <pre><code>[df["A"],df["B"],df["C"]] = [df["A"],df["B"],df["C"]].apply(pd.to_numeric, errors='coerce')
  </code></pre>