Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.9/dist-packages/pandas/core/array_algos/transforms.py: 22%

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 ( 

13 AxisInt, 

14 Scalar, 

15 ) 

16 

17 

18def shift( 

19 values: np.ndarray, periods: int, axis: AxisInt, fill_value: Scalar 

20) -> np.ndarray: 

21 new_values = values 

22 

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

24 return new_values.copy() 

25 

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

27 f_ordered = values.flags.f_contiguous 

28 if f_ordered: 

29 new_values = new_values.T 

30 axis = new_values.ndim - axis - 1 

31 

32 if new_values.size: 

33 new_values = np.roll( 

34 new_values, 

35 np.intp(periods), 

36 axis=axis, 

37 ) 

38 

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

40 if periods > 0: 

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

42 else: 

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

44 new_values[tuple(axis_indexer)] = fill_value 

45 

46 # restore original order 

47 if f_ordered: 

48 new_values = new_values.T 

49 

50 return new_values