title: Pandas dataframe Timedelta format: with days or with cumulative hours
body: <p>I am trying to understand that depending on what does pandas show Timedelta values either with 'days' or with cumulative number of hours.</p>
  
  <p>In the following example, I take a Timedelta column and calculate its cumulative sum:</p>
  
  <pre class="lang-py prettyprint-override"><code>In [1]: import pandas as pd                                                                                                                                                      
  
  In [2]: pd.__version__                                                                                                                                                           
  Out[2]: '1.0.3'
  
  In [3]: df = pd.DataFrame( 
     ...:     [ 
     ...:         "01:07:37", 
     ...:         "13:16:44", 
     ...:         "11:09:56", 
     ...:         "12:05:00", 
     ...:         "01:33:01", 
     ...:     ], 
     ...:     columns=["Duration"], 
     ...: )                                                                                                                                                                        
  
  In [4]: df.loc[:, 'Duration'] = pd.to_timedelta(df['Duration']) 
     ...: df.loc[:, 'Cumulative'] = df['Duration'].cumsum() 
     ...:  
     ...: df                                                                                                                                                                       
  Out[4]: 
    Duration      Cumulative
  0 01:07:37 0 days 01:07:37
  1 13:16:44 0 days 14:24:21
  2 11:09:56 1 days 01:34:17
  3 12:05:00 1 days 13:39:17
  4 01:33:01 1 days 15:12:18
  </code></pre>
  
  <p>In the resulting dataframe the new column (<code>Cumulative</code>) shows 'days' while the original column (<code>Duration</code>) shows cumulative number of hours.</p>
  
  <p>The two columns are of the same data type.</p>
  
  <pre><code>In [5]: df.dtypes                                                                                                                                                                
  Out[5]: 
  Duration      timedelta64[ns]
  Cumulative    timedelta64[ns]
  dtype: object
  </code></pre>
  
  <p>Furthermore, when I look at the first row it shows the 'number of hours' format, but, when I look at individual values, it returns them in the Timedelta('N days HH:MM:SS') format.</p>
  
  <pre><code>In [6]: df.iloc[0, :]                                                                                                                                                            
  Out[6]: 
  Duration     01:07:37
  Cumulative   01:07:37
  Name: 0, dtype: timedelta64[ns]
  
  In [7]: df['Duration'][0], df['Cumulative'][0]                                                                                                                                   
  Out[7]: (Timedelta('0 days 01:07:37'), Timedelta('0 days 01:07:37'))
  </code></pre>
  
  <p>So my question is that why does this change occur and how can I control it?</p>
  
  <h1>EDIT</h1>
  
  <p>As @Moosa Saadat and @Quang Hoang pointed out, the shift between the different formats occurs when <strong>any</strong> of the Timedelta values surpasses the 24-hour threshold.</p>
  
  <p>As I did not find a built-in way to do the shift, here is a small helper function that prints Timedelta values in a cumulative hours format.</p>
  
  <pre class="lang-py prettyprint-override"><code>In [4]: def days_to_cumhours(timedelta): 
     ...:     hours = timedelta.components[0] * 24 + timedelta.components[1] 
     ...:  
     ...:     return f"{hours:0&gt;2}:{timedelta.components[2]:0&gt;2}:{timedelta.components[3]:0&gt;2}"                                                                                                                                                                  
  
  In [5]: df['Cumulative'].apply(days_to_cumhours)                                                                                                                                 
  Out[5]: 
  0    01:07:37
  1    14:24:21
  2    25:34:17
  3    37:39:17
  4    39:12:18
  Name: Cumulative, dtype: object
  </code></pre>