Compare 2 Consecutive Rows And Assign Increasing Value If Different (using Pandas)

I have a dataframe df_in like so: import pandas as pd dic_in = {'A':['aa','aa','bb','cc','cc','cc','cc','dd','dd','dd','ee'], 'B':['200','200','200','400','400','500','700',

Solution 1:

Use shift and any to compare consecutive rows, using True to indicate where the value should change. Then take the cumulative sum with cumsum to get the increasing value:

df_in['value'] = (df_in[['A', 'B']] != df_in[['A', 'B']].shift()).any(axis=1)
df_in['value'] = df_in['value'].cumsum()

Alternatively, condensing it to one line:

df_in['value'] = (df_in[['A', 'B']] != df_in[['A', 'B']].shift()).any(axis=1).cumsum()

The resulting output:

AB   C  value
0   aa  200  da      11   aa  200  cs      12   bb  200  fr      23   cc  400  fs      34   cc  400  se      35   cc  500  at      46   cc  700  yu      57dd700  j5      68dd9003179dd900  ds      710  ee  200  sz      8