TimezoneTransformer

TimezoneTransformer

Converts the DataFrame index from UTC to a target timezone.

Basic Usage

from epftoolbox2.data.transformers import TimezoneTransformer

transformer = TimezoneTransformer(target_tz="Europe/Warsaw")
df = transformer.transform(df)

Parameters

Parameter	Type	Required	Description
target_tz	str	Yes	Target timezone name

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Pipeline Order

Caution

The order of transformers matters! Apply TimezoneTransformer at the right stage:

1. Before LagTransformer: Lags are calculated in local time
2. After LagTransformer: Lags are calculated in UTC

Recommended Pipeline Order

It is recommended to add ResampleTransformer after TimezoneTransformer to fill gaps created by daylight saving time transitions:

pipeline = (
    DataPipeline()
    .add_source(EntsoeSource(...))  # Output: UTC
    .add_transformer(LagTransformer(...))  # Lags in UTC
    .add_transformer(TimezoneTransformer(target_tz="Europe/Warsaw"))  # Creates DST gaps
    .add_transformer(ResampleTransformer(freq="1h"))  # Fills DST gaps
)

Tip

During DST spring-forward, one hour is skipped (e.g., 2:00 AM). ResampleTransformer will interpolate to fill this gap.

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Timezone List

For a complete list of valid timezone names, see: List of tz database time zones

Common Timezones

Timezone	Description
"Europe/Warsaw"	Poland (CET/CEST)
"Europe/Berlin"	Germany (CET/CEST)
"Europe/Paris"	France (CET/CEST)
"Europe/London"	UK (GMT/BST)
"America/New_York"	US Eastern
"UTC"	Coordinated Universal Time

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Behavior

• Naive index: Localized to UTC, then converted
• Timezone-aware index: Directly converted

# Input: 2024-01-01 00:00:00+00:00 (UTC)
# Output: 2024-01-01 01:00:00+01:00 (Warsaw = CET)