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ApplyApply, Aggregate, Transform, MapApply, Aggregate, Transform, MapBugNeeds InfoClarification about behavior needed to assess issueClarification about behavior needed to assess issueWarningsWarnings that appear or should be added to pandasWarnings that appear or should be added to pandas
Description
Pandas version checks
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I have checked that this issue has not already been reported.
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I have confirmed this bug exists on the latest version of pandas.
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I have confirmed this bug exists on the main branch of pandas.
Reproducible Example
import numpy as np
import pandas as pd
n_rows = 1_000
group_size = 10
n_random_cols = 200
data = {"id": np.repeat(np.arange(n_rows // group_size), group_size)}
for i in range(n_random_cols):
data[f"col_{i}"] = np.random.randn(n_rows)
df = pd.DataFrame(data)
# PerformanceWarning when as_index is False
named_agg_without_index_warning_df = (
df
.groupby('id', as_index=False)
.agg(**{
column: pd.NamedAgg(column=column, aggfunc="mean")
for column in df.columns if column != "id"
})
)
# no warnings when as_index is True
named_agg_with_index_ok_df = (
df
.groupby('id', as_index=True)
.agg(**{
column: pd.NamedAgg(column=column, aggfunc="mean")
for column in df.columns if column != "id"
})
)
# no warnings when using dict agg no matter what as_index is
dict_agg_ok_df = (
df
.groupby('id', as_index=False)
.agg({
column: "mean"
for column in df.columns if column != "id"
})
)
Issue Description
there is an inconsistent behavior (PerformanceWarning) of agg when as_index
is True/False. Please refer to the example above.
Expected Behavior
No PerformanceWarning
is raised when as_index=False
Installed Versions
v2.3.0
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Assignees
Labels
ApplyApply, Aggregate, Transform, MapApply, Aggregate, Transform, MapBugNeeds InfoClarification about behavior needed to assess issueClarification about behavior needed to assess issueWarningsWarnings that appear or should be added to pandasWarnings that appear or should be added to pandas