Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/pandas/core/array_algos/transforms.py: 24%

1""" 

2transforms.py is for shape-preserving functions. 

3""" 

4 

5from __future__ import annotations 

6 

7from typing import TYPE_CHECKING 

8 

9import numpy as np 

10 

11if TYPE_CHECKING: 

12 from pandas._typing import Scalar 

13 

14 

15def shift(values: np.ndarray, periods: int, fill_value: Scalar) -> np.ndarray: 

16 new_values = values 

17 

18 if periods == 0 or values.size == 0: 

19 return new_values.copy() 

20 

21 # Always shift along the last axis. 

22 axis = new_values.ndim - 1 

23 

24 # make sure array sent to np.roll is c_contiguous 

25 f_ordered = values.flags.f_contiguous 

26 if f_ordered: 

27 new_values = new_values.T 

28 axis = 0 

29 

30 if new_values.size: 

31 new_values = np.roll( 

32 new_values, 

33 np.intp(periods), 

34 axis=axis, 

35 ) 

36 

37 axis_indexer = [slice(None)] * values.ndim 

38 if periods > 0: 

39 axis_indexer[axis] = slice(None, periods) 

40 else: 

41 axis_indexer[axis] = slice(periods, None) 

42 new_values[tuple(axis_indexer)] = fill_value 

43 

44 # restore original order 

45 if f_ordered: 

46 new_values = new_values.T 

47 

48 return new_values