title: Matplotlib: how to plot a line with categorical data on the x-axis?
body: <p>I am trying to plot <strong>a few lines</strong> (not a bar plot, as in <a href="https://stackoverflow.com/questions/7559242/matplotlib-strings-as-labels-on-x-axis">this case</a>). My y values are <code>float</code>, whereas x values are <code>categorical data</code>. How to do this in <code>matplotlib</code>?</p>
  
  <p>My values:</p>
  
  <pre><code>data1=[5.65,7.61,8.17,7.60,9.54]
  data2=[7.61,16.17,16.18,19.54,19.81] 
  data3=[29.55,30.24,31.51,36.40,35.47]
  </code></pre>
  
  <p>My categories:</p>
  
  <pre><code>x_axis=['A','B','C','D','E']
  </code></pre>
  
  <p>The code I am using, which does not give me what I want:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  fig=plt.figure() #Creates a new figure
  ax1=fig.add_subplot(111) #Plot with: 1 row, 1 column, first subplot.
  line1 = ax1.plot(str(x_axis), data1,'ko-',label='line1') #Plotting data1
  line2 = ax1.plot(str(x_axis), data2,'ro-',label='line2') #Plotting data2
  line3 = ax1.plot(str(x_axis), data3,'mo-',label='line3') #Plotting data3
  plt.xticks(range(len(data3)), x_axis, size='small')
  ax1.set_ylim(0,51)
  ax1.set_ylabel('y values',fontsize=12)
  #Assigning labels
  lines = line1+line2+line3
  labels = [l.get_label() for l in lines]
  ax1.legend(lines,labels,loc='upper center', prop={'size':10}, bbox_to_anchor=(0.5, -0.13), fancybox=True, shadow=True, ncol=5)
  ax1.set_xlabel('Categories',fontsize=14)
  plt.setp(ax2.get_xticklabels(), visible=True)
  title_string=('Plotting categories vs y values in matplotlib')
  plt.suptitle(title_string, y=1.0, fontsize=17)
  fig.tight_layout()
  fig.subplots_adjust(top=0.92,bottom=0.2)
  plt.show() 
  plt.savefig('myplot.jpg',bbox_inches='tight')
  plt.close()
  </code></pre>