title: How do I fix this type error ('value' must be an instance of str or bytes, not a float) on Python
body: <p>I want to plot a graph for Covid-19 in India and so far there's no problem when I manually input my data as x and y axis. But since the data is quite long and when I want to read it as .csv file, it gives me this error <em>'value' must be an instance of str or bytes, not a float</em>. I have also try to wrap <em>int(corona_case)</em>, but giving me another new error, <em>cannot convert the series to &lt;class 'int'</em>. Also I would be very appreciate if someone can suggest me tutorials on plotting graph involving datetime using python since this is my first time learning python.
  I am using Python 3.</p>
  <p>p/s I seem can't find a way to share my csv file so I am gonna leave it in snippet.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
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  <pre class="snippet-code-html lang-html prettyprint-override"><code>import pandas as pd
  from datetime import datetime, timedelta
  from matplotlib import pyplot as plt
  from matplotlib import dates as mpl_dates
  import numpy as np
  
  plt.style.use('seaborn')
  
  data = pd.read_csv('india.csv')
  corona_date = data['Date']
  corona_case = data['Case']
   
  plt.plot_date (corona_date, corona_case, linestyle='solid')
  
  plt.gcf().autofmt_xdate()
  
  plt.title('COVID-19 in India')
  plt.xlabel('Date')
  plt.ylabel('Cumulative Case')
  
  plt.tight_layout()
  
  plt.show()</code></pre>
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  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>Date,Case
  2020-09-30,6225763
  2020-10-01,6312584
  2020-10-02,6394068
  2020-10-03,6473544
  2020-10-04,6549373
  2020-10-05,6623815
  2020-10-06,6685082</code></pre>
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