title: ValueError: could not convert string to float: '?'
body: <p>I have tried to run a SVM program, and I got the above error. The code is here below. Please point out the error in it.</p>
  
  <pre><code>import numpy as np
  import pandas as pd
  from sklearn import svm
  from sklearn.model_selection import train_test_split
  data = pd.read_csv('risk_factors_cervical_cancer.csv')
  X = np.array(data[[#some data elements]])
  y = np.array(data[#some data elements])
  print(X)
  print(y)
  print(X.shape)
  X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.25, 
  random_state=30)
  classifier = svm.SVC()
  classifier.fit(X_train, y_train)    #the error occurs here 
  y_pred = svm.predict(X_test)
  acc = accuracy_score(y_test, y_pred)
  </code></pre>
  
  <p>`</p>