pandas: "Concatenation will no longer sort" wording is very inconsistent

The wording in the update docs is (emphasis added):

In a future version of pandas pandas.concat() will no longer sort the non-concatenation axis when it is not already aligned. (…)

To keep the previous behavior (sorting) and silence the warning, pass sort=True. To accept the future behavior (no sorting), pass sort=False

https://pandas-docs.github.io/pandas-docs-travis/whatsnew.html#concatenation-will-no-longer-sort

But the wording in the `FutureWarning` messages is (emphasis added):

Sorting because non-concatenation axis is not aligned. A future version of pandas will change to not sort by default.

To accept the future behavior, pass sort=True. To retain the current behavior and silence the warning, pass sort=False

https://github.com/pandas-dev/pandas/blob/c4da79b5b322c73d8e61d1cb98ac4ab1e2438b40/pandas/core/indexes/api.py

It needs to be clearer that current default is still sort=True but will revert to sort=False in a future version.

About this issue

Original URL
State: closed
Created 6 years ago
Comments: 15 (7 by maintainers)

Commits related to this issue

default value for sort added to concatenation: https://github.com/pandas-dev/pandas/issues/21112 — committed to b3by/antools by b3by 6 years ago

Most upvoted comments

Ok, I found it. It actually was an append command (not concat or merge). Adding the sort parameter did remove the warning. I added the sort=False parameter to this: df_B = df_A.append(df_B, verify_integrity=True, sort=False).copy()

techvslife on May 23, 2018

also: Currently the warning doesn’t get silenced if you pass “sort=False” (i.e. the true future default behavior)–presumably there should be no warning as long as the sort parameter is explicitly set (passed).

techvslife on May 21, 2018

You can make warnings raise. Something like

import warnings

warnings.simplefilter("error")
<your code>

On Mon, May 21, 2018 at 2:06 PM, techvslife notifications@github.com wrote:

Sorry, I’m not having luck reproducing with a small example; may not be a concat command, but a merge command instead. Unfortunately I don’t know what line in code is triggering the warning from the warning.

— You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub https://github.com/pandas-dev/pandas/issues/21112#issuecomment-390751519, or mute the thread https://github.com/notifications/unsubscribe-auth/ABQHIgfJzYneJoqF0VaPK1WMQhQlSp9lks5t0xAngaJpZM4UD6_G .

TomAugspurger on May 21, 2018