title: ValueError: 'label' must be of length 'x' using matplotlib
body: <p>I am trying to plot pie chart using varible data.</p>
  
  <p>Below is my code. both <strong>Postive_percentage</strong> and <strong>topic</strong> is the <strong>list</strong> whose data comes from other part of code and through various operations. I have posted the value of <strong>Postive_percentage</strong> and <strong>topic</strong> from the output. </p>
  
  <p>I am new to python thats why i am not able to understand the issue. <strong>Postive_percentage</strong>,  <strong>topic</strong> and <strong>colors</strong> have 7 variables and still it is giving me this error. </p>
  
  <pre><code>#topic and Postive_percentage copied from output and was not manually inserted by me. 
      topic = ['VirginAmerica', 'UnitedAirline', 'SouthWestAirline', 'USAirline', 'AmericanAirline', 'SpiritAirline', 'DeltaAirline']
      Postive_percentage = [3.917525773195876, 10.0, 6.666666666666667, 10.0, 3.0, 5.0, 5.0]
  
  
  sizes = Postive_percentage
      print(sizes)
      labels = str(topic)
     # makeitastring = ''.join(map(str, labels))
      print(labels)
      colors = ['yellowgreen', 'lightgreen', 'darkgreen', 'gold', 'red', 'lightsalmon', 'darkred']
      plt.pie(sizes, explode=None, labels=labels, colors=colors, autopct='%1.1f%%', shadow=True, startangle=90)   #line 240
      #plt.pie(sizes, labels, colors)
      plt.axis('equal')
      plt.legend()
      plt.show()
  </code></pre>
  
  <p>this is the error that is being generated.</p>
  
  <pre><code>Traceback (most recent call last):
    File "C:/Users/Aryana/Desktop/Sentimental-Analysis-on-Twitter-master/senti_twitter.py", line 248, in &lt;module&gt;
      main()
    File "C:/Users/Aryana/Desktop/Sentimental-Analysis-on-Twitter-master/senti_twitter.py", line 240, in main
      plt.pie(sizes, explode=None, labels=labels, colors=colors, autopct='%1.1f%%', shadow=True, startangle=90)
    File "C:\Users\Aryana\Desktop\Sentimental-Analysis-on-Twitter-master\venv\lib\site-packages\matplotlib\pyplot.py", line 3338, in pie
      frame=frame, rotatelabels=rotatelabels, data=data)
    File "C:\Users\Aryana\Desktop\Sentimental-Analysis-on-Twitter-master\venv\lib\site-packages\matplotlib\__init__.py", line 1855, in inner
      return func(ax, *args, **kwargs)
    File "C:\Users\Aryana\Desktop\Sentimental-Analysis-on-Twitter-master\venv\lib\site-packages\matplotlib\axes\_axes.py", line 2858, in pie
      raise ValueError("'label' must be of length 'x'")
  ValueError: 'label' must be of length 'x'
  </code></pre>