title: What does this line mean in simple linear regression?
body: <p>I am new to machine learning. While practicing code,</p>
  
  <pre><code>plt.scatter(train.FUELCONSUMPTION_COMB, train.CO2EMISSIONS, color='blue')
  plt.plot(train_x, regr.intercept_[0] + regr.coef_[0][0] * train_x, '-r' )
  plt.xlabel("Fuel Consumption")
  plt.ylabel("Emmission")
  plt.show()
  </code></pre>
  
  <p>In plt.plot(train_x, regr.intercept_[0] + regr.coef_[0][0] * train_x, '-r' ), what does [0] and [0][0] mean in regr.intercept_[0] + regr.coef_[0][0] ?</p>