Pandas: implementing merging DataFrames that have timezone-aware datetime columns
I need help solving I'm writing unit tests and I'm converting an old project and I need some guidance on I can't seem to get I keep running into I need some guidance on I'm working with an scenario when trying to merge two DataFrames that both contain timezone-aware datetime columns... My goal is to combine the DataFrames based on a common datetime index, but I'm getting unexpected results where the merge seems to create duplicate rows instead of aligning them correctly based on the timestamps. Here’s a simplified version of my DataFrames: ```python import pandas as pd import pytz df1 = pd.DataFrame({ 'timestamp': pd.date_range('2023-01-01 12:00', periods=3, freq='H').tz_localize('UTC'), 'value': [10, 20, 30] }) df2 = pd.DataFrame({ 'timestamp': pd.date_range('2023-01-01 12:30', periods=3, freq='H').tz_localize('UTC'), 'value': [100, 200, 300] }) print(df1) print(df2) ``` When I attempt to merge these DataFrames: ```python merged_df = pd.merge(df1, df2, on='timestamp', how='outer') print(merged_df) ``` I expected to see the merged result aligned correctly based on the `timestamp`, but instead, I see that the rows do not align as I anticipated. The output is: ``` timestamp value_x value_y 0 2023-01-01 12:00:00+00:00 10.0 NaN 1 2023-01-01 12:01:00+00:00 NaN 100.0 2 2023-01-01 12:02:00+00:00 NaN 200.0 3 2023-01-01 12:03:00+00:00 NaN 300.0 ``` It's as if the merge is treating the timestamps as distinct even though they should align. I’ve checked that both DataFrames are indeed timezone-aware and localized to 'UTC'. I tried converting the timestamps to naive datetime using `dt.tz_localize(None)` before the merge, but that resulted in a loss of timezone information, which I need. Any suggestions on how to properly merge these DataFrames while keeping the timezone information intact? Is there something I'm missing about how pandas handles timezone-aware datetime columns during merges? The stack includes Python and several other technologies. I'd be grateful for any help. Thanks in advance! Am I approaching this the right way? I'm coming from a different tech stack and learning Python. Am I approaching this the right way? For context: I'm using Python on Windows 10. Any ideas what could be causing this? My team is using Python for this mobile app. Am I missing something obvious?