Complex pivot and resample
<p>I'm not sure where to start with this so apologies for my lack of an attempt.</p>

<p>This is the initial shape of my data:</p>

<pre><code>df = pd.DataFrame({
    'Year-Mth': ['1900-01'
                 ,'1901-02'
                 ,'1903-02'
                 ,'1903-03'
                 ,'1903-04'
                 ,'1911-08'
                 ,'1911-09'], 
    'Category': ['A','A','B','B','B','B','B'], 
    'SubCategory': ['X','Y','Y','Y','Z','Q','Y'], 
    'counter': [1,1,1,1,1,1,1]
})

df
</code></pre>

<p>This is the result I'd like to get to - the Mth-Year in the below has been resampled to 4 year buckets:</p>

<p><a href="http://i.stack.imgur.com/sWkYR.png" rel="nofollow"><img src="http://i.stack.imgur.com/sWkYR.png" alt="enter image description here"></a></p>

<p>If possible I'd like to do this via a process that makes 'Year-Mth' resamplable - so I can easily switch to different buckets.</p>

<pre><code>cols = [df.SubCategory, pd.to_datetime(df['Year-Mth']), df.Category]
df1 = df.set_index(cols).counter

df1.unstack('Year-Mth').T.resample('60M', how='sum').stack(0).swaplevel(0, 1).sort_index().fillna('')
</code></pre>

<p><a href="http://i.stack.imgur.com/7trRO.png" rel="nofollow"><img src="http://i.stack.imgur.com/7trRO.png" alt="enter image description here"></a></p>

python pandas