title: How to convert string into float value in the dataframe
body: <p>We are facing an error when we have a column which have datatype as string and the value like 
  col1  col2 
  1      .89</p>
  
  <p>So, when we are using </p>
  
  <pre><code>def azureml_main(dataframe1 = None, dataframe2 = None):
  
      # Execution logic goes here
      print('Input pandas.DataFrame #1:')
      import pandas as pd
      import numpy as np
      from sklearn.kernel_approximation import RBFSampler
      x =dataframe1.iloc[:,2:1080]
      print x
      df1 = dataframe1[['colname']]
  
      change = np.array(df1)
      b = change.ravel()
      print b
      rbf_feature = RBFSampler(gamma=1, n_components=100,random_state=1)
      print rbf_feature
      print "test"
      X_features = rbf_feature.fit_transform(x)
  </code></pre>
  
  <p>After this we are getting error as cannt convert non int into type float</p>