pandas.errors.PerformanceWarning#

exceptionpandas.errors.PerformanceWarning[source] #

Warning raised when there is a possible performance impact.

See also

DataFrame.set_index

Set the DataFrame index using existing columns.

DataFrame.loc

Access a group of rows and columns by label(s) or a boolean array.

Examples

>>> df = pd.DataFrame(
...  {"jim": [0, 0, 1, 1], "joe": ["x", "x", "z", "y"], "jolie": [1, 2, 3, 4]}
... )
>>> df = df.set_index(["jim", "joe"])
>>> df
 jolie
jim joe
0 x 1
 x 2
1 z 3
 y 4
>>> df.loc[(1, "z")]
# PerformanceWarning: indexing past lexsort depth may impact performance.
df.loc[(1, 'z')]
 jolie
jim joe
1 z 3
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