maxframe.liteframe.LiteFrame.shift#

LiteFrame.shift(periods=1, fill_value=None, columns=None)#

Shift rows by periods positions.

Positive periods shifts data forward (down); negative shifts backward (up). Positions introduced by the shift are filled with fill_value (default: null).

Parameters:

  • periods (int, default 1) – Number of positions to shift. Positive = forward, negative = backward.

  • fill_value (scalar, default None) – Value to fill positions introduced by shifting. None produces null.

  • columns (str, list of str, or None, default None) – Column(s) to shift. If None, all columns are shifted. Non-selected columns are passed through unchanged.

Returns:

Shifted LiteFrame with the same shape and columns. Output dtypes depend on the input dtype and fill_value: when fill_value is None (the default) input dtypes are preserved; when a fill_value is supplied a column may be widened (e.g. an integer column with a float fill becomes Float64, a string fill becomes String). Boolean columns coerce numeric fills to bool; decimal columns derive precision from the fill value; a string fill on a boolean column is rejected at plan time. Non-selected (passthrough) columns keep their input dtypes.

Return type:

LiteFrame

See also

diff

Compute the difference between consecutive rows.

pct_change

Compute percent change over given periods.

rolling

Provide rolling-window calculations.

Examples

>>> import maxframe.liteframe as mlf
>>> lf = mlf.LiteFrame({'a': [1, 2, 3, 4]})
>>> result = lf.shift(1)
>>> result.execute()
     a
0  NaN
1  1.0
2  2.0
3  3.0