title: plot iris dataset using matplotlib.pyplot & ListedColormap?
body: <p>I wrote below code to plot sepal width vs. sepal length for the famous iris dataset. I think it's supposed to plot the dots with 3 different colors (for the 3 different labels: 'setosa', 'versicolor', 'virginica'), but it only plots all the dots with one same color.</p>
  
  <p>How can I use the labels to plot the dots with three different colors?</p>
  
  <p><a href="https://i.stack.imgur.com/XwLnI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XwLnIm.png" alt="screenshot"></a></p>
  
  <pre><code>import numpy as np
  import pandas as pd
  from sklearn.datasets import load_iris
  
  iris = load_iris()
  print(list(iris.feature_names))
  print (iris.target)
  data = pd.DataFrame(iris.data)
  data.columns = iris.feature_names
  data['label'] = iris.target
  data.head()
  import matplotlib.pyplot as plt
  from matplotlib.colors import ListedColormap
  cmap_bold = ListedColormap(['#FF0000', '#00FF00', '#0000FF'])
  
  # create a scatter plot of SEPAL WIDTH versus SEPAL LENGTH and color by SPECIES
  plt.scatter(data['sepal length (cm)'], data['sepal width (cm)'], cmap=cmap_bold)
  plt.title("sepal width vs sepal length")
  plt.xlabel('x label')
  plt.ylabel('y label')
  plt.show()
  </code></pre>