ENH: align timedelta fractional seconds

[wjandrea]

Feature Type

• Adding new functionality to pandas
• Changing existing functionality in pandas
• Removing existing functionality in pandas

Problem Description

It's hard to read a column of timedeltas with fractional seconds of different precisions because it's not aligned, for example:

0             0 days 00:00:01
1      0 days 00:00:00.500000
2   0 days 00:00:00.333333333
dtype: timedelta64[ns]

It'd be easier to read like this:

0   0 days 00:00:01
1   0 days 00:00:00.500000
2   0 days 00:00:00.333333333
dtype: timedelta64[ns]

or

0   0 days 00:00:01.000000000
1   0 days 00:00:00.500000000
2   0 days 00:00:00.333333333
dtype: timedelta64[ns]

To reproduce:

s = 1 / pd.Series(np.arange(3)+1)
td = pd.to_timedelta(s, unit='s')
td

Feature Description

Add padding on the right.

In this case, it can be done by left-justifying to the largest size:

n = td.astype(str).apply(len).max()
td.astype(str).str.ljust(n)

0    0 days 00:00:01          
1    0 days 00:00:00.500000   
2    0 days 00:00:00.333333333
dtype: object

But of course, this wouldn't work for different numbers of days. For example:

td1 = pd.concat([td, pd.Series(pd.Timedelta(days=4000))])

0    0 days 00:00:01          
1    0 days 00:00:00.500000   
2    0 days 00:00:00.333333333
0    4000 days 00:00:00       
dtype: object

If timedeltas had a .replace() method so you could zero out the days, then it would work, but AFAIK such a method doesn't exist.

BTW, the same thing is already implemented for floats and datetimes.

>>> s*10
0    10.000000
1     5.000000
2     3.333333
dtype: float64
>>> pd.Timestamp(0) + td
0   1970-01-01 00:00:01.000000000
1   1970-01-01 00:00:00.500000000
2   1970-01-01 00:00:00.333333333
dtype: datetime64[ns]

Alternative Solutions

n/a

Additional Context

No response

[rhshadrach]

Thanks for the report - agreed this would be an improvement. PRs to fix are welcome.

[wjandrea]

PRs to fix are welcome.

Working on one :) but this functionality is buried in some Cython code (_Timedelta._repr_base), which I've never written before, so it's a bit of a slog.

[mafaldam]

still working on this @wjandrea ?

[mafaldam]

Hi @wjandrea , just a friendly follow-up on my previous comment. Since I haven't heard back, I wanted to let you know that I'm planning to start working on this soon. Your input would be valuable before I begin. Thanks!

[mafaldam]

take

[sofiasimass]

take

[wjandrea]

@mafaldam Yeah, I actually made quite a bit of progress on this, but it's setting up the build system that I'm stuck on right now. Let me plug away at it a little while and I'll let you know. Sorry for not replying sooner :)