BUG: `to_datetime` does not support `format="%y%m%d"`

[yasirroni]

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Reproducible Example

import pandas as pd

...

# using both 05 and 95 data on 'YEAR' is not supported
pd.to_datetime(df[['YEAR', 'MONTH', 'DAY']], format="%y%m%d")

Issue Description

Python support %y as shown in https://docs.python.org/3/library/datetime.html#strftime-and-strptime-format-codes

But, using format="%y%m%d", error occurs:

ValueError: time data "950101" doesn't match format "%Y%m%d", at position 0. You might want to try:
    - passing `format` if your strings have a consistent format;
    - passing `format='ISO8601'` if your strings are all ISO8601 but not necessarily in exactly the same format;
    - passing `format='mixed'`, and the format will be inferred for each element individually. You might want to use `dayfirst` alongside this.

Expected Behavior

Pandas should also support %y

Installed Versions

2.0.3

The format="%y%m%d" expects each of the values to be in this format. Here looks like each string is at max 2 digits which makes the format incompatible with the values.

[lithomas1]

Can you paste a minimum reproducible example?
(code that I can copy paste and run. In this case, what is df?)

Running

pd.to_datetime(["950101", "050101"], format="%y%m%d")

works for me.

I notice in the error message it mentions format "%Y%m%d".
You might want to check if you typo'ed, by using an upper case Y instead of a lower case one.

[yasirroni]

pd.to_datetime(["950101", "050101"], format="%y%m%d")

Thanks for the answer @lithomas1, I test your code, and that works. But, below code return error:

import pandas as pd

df = pd.DataFrame({
    'YEAR': [95, 96, 98],
    'MONTH': [1, 2, 12],
    'DAY': [1, 10, 30]
})
pd.to_datetime(df[['YEAR', 'MONTH', 'DAY']], format="%y%m%d")

But, below code didn't (it silently use %Y%m%d):

df = pd.DataFrame({
    'YEAR': [1995, 1996, 1998],
    'MONTH': [1, 2, 12],
    'DAY': [1, 10, 30]
})
pd.to_datetime(df[['YEAR', 'MONTH', 'DAY']], format="%y%m%d")

[MarcoGorelli]

thanks for the report - this looks wrong indeed

[yasirroni]

@MarcoGorelli Can I ask you why the fix is in the docs instead of supporting DataFrame object? And if I able to make PR that support DataFrame, can you accept it?