Create preparation.py

Added function for padding/unpadding of the data.

preparation.py

@@ -0,0 +1,63 @@
+"""
+This module does padding and unpadding the data
+"""
+import pandas as pd
+import numpy as np
+
+def pad_time_series(series, target_length, padding_value=None):
+    """
+    Pads the given time series to the target length.
+
+    Parameters:
+    - series: pd.series
+        The input time series with datetime index.
+    - target_length: int
+        The desired length after padding.
+    - padding_value: float or None
+        The value to pad with. If None, will use the mean of the series.
+    Returns:
+    - pd.series
+        The padded time series.
+    """
+    # Determine current length
+    current_length = len(series)
+
+    # If current length is already equal to or greater than target, return the series
+    if current_length >= target_length:
+        return series
+
+    # Determine padding length
+    padding_length = target_length - current_length
+
+    # If no padding value is provided, calculate a reasonable padding value
+    if padding_value is None:
+        padding_value = series.mean()  # You could also use median or any other method
+
+    # Create a padding Series
+    padding_index = pd.date_range(start=series.index[-1] + pd.Timedelta(days=1), 
+                                   periods=padding_length, freq='D')
+    padding_series = pd.Series(padding_value, index=padding_index)
+
+    # Concatenate the original series with the padding
+    padded_series = pd.concat([series, padding_series])
+
+    return padded_series
+
+
+def unpad_time_series(padded_series, original_length):
+    """
+    Unpads the given time series to the original length.
+
+    Parameters:
+    - padded_series: pd.Series
+        The padded time series with datetime index.
+    - original_length: int
+        The original length of the series before padding.
+
+    Returns:
+    - pd.Series
+        The unpadded time series.
+    """
+    # Return the original length of the series
+    return padded_series.iloc[:original_length]  
+