title: Unable to limit float to two decimal places in Pandas
body: <p>I have some variety of data which looks like below</p>
  
  <pre><code>data1  = [[(271.760309837,)], [(289.247745329,)]]
  data2 = [(u'A', datetime.datetime(2019, 8, 23, 0, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 2.66666666666667), (u'B', datetime.datetime(2019, 8, 23, 0, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 3.66666666666667), (u'C', datetime.datetime(2019, 8, 23, 0, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 12.25), (u'D', datetime.datetime(2019, 8, 23, 0, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 5.875), (u'E', datetime.datetime(2019, 8, 23, 0, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 9.06451612903226), (u'F', datetime.datetime(2019, 8, 23, 1, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 5.363636363636), (u'G', datetime.datetime(2019, 8, 23, 1, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 3.5), (u'H', datetime.datetime(2019, 8, 23, 1, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 9.53125), (u'I', datetime.datetime(2019, 8, 23, 1, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 3.2), (u'J', datetime.datetime(2019, 8, 23, 1, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 7.0967741354839), (u'K', datetime.datetime(2019, 8, 23, 2, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 3.25), (u'L', datetime.datetime(2019, 8, 23, 2, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 5.1153846153846), (u'M', datetime.datetime(2019, 8, 23, 2, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 6.387096419355), (u'N', datetime.datetime(2019, 8, 23, 2, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 4.47058529412), (u'O', datetime.datetime(2019, 8, 23, 2, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 3.727272727273), (u'P', datetime.datetime(2019, 8, 23, 3, 0, tzinfo=psycopg2.tz.FixedOffsetTimezone(offset=0, name=None)), 5.2)]
  data3 = [[('A', 204.593564568), ('B', 217.421341061), ('C', 237.296250326), ('D', 217.464281998), ('E', 206.329901299)], [('F', 210.297625953), ('G', 228.117692718), ('H', 4), ('I', 265.319671257), ('K',)]]
  </code></pre>
  
  <p>As you can see, the float values have couple of digits after decimal. I would like to make any occurrence of float value to a one digit after decimal. Looking up for answers online, the most common suggestion I came across was to use the <code>round()</code> function. So I tried this</p>
  
  <pre><code>import pandas as pd
  import datetime
  import psycopg2
  
  df = pd.DataFrame(data1).round(2).values.tolist()
  df = pd.DataFrame(data2).round(2).values.tolist()
  df = pd.DataFrame(data3).round(2).values.tolist()
  </code></pre>
  
  <p>But it only worked for <code>data2</code> while the other two data didn't show any rounding.</p>
  
  <p>Furthermore, I also tried using <code>numpy</code> to achieve the result</p>
  
  <pre><code>df = pd.Dataframe(data1)
  np.round(df, decimals=2).values
  
  
  df = pd.Dataframe(data2)
  np.round(df, decimals=2).values
  
  
  df = pd.Dataframe(data2)
  np.round(df, decimals=2).values
  </code></pre>
  
  <p>But again it only worked for <code>data2</code>. How can I ensure the rounding or limiting it to two decimal places is consistent across any data formats in pandas?</p>