Python 3.4+statisticsfunction

statistics.mean

mean

Arithmetic mean (average) of the data.

Syntax

statistics.mean(data)

mean is exact (fractions under the hood) and preserves the input type: a list of ints can come back as an int, Fractions stay Fractions, Decimals stay Decimals; when you just want a float and speed, use fmean. It is also dragged by outliers — a single freak value shifts it noticeably while median barely moves. Empty data raises StatisticsError rather than returning 0.

Examples

import statistics
print(statistics.mean([1, 2, 3, 4]))   # → 2.5
print(statistics.mean([1, 2, 3]))   # → 2
print(round(statistics.mean([4, 5, 3, 5, 4]), 2))   # → 4.2
print(statistics.mean([1, 2, 3, 100]), statistics.median([1, 2, 3, 100]))   # → 26.5 2.5
print(statistics.mean([])) # → StatisticsError

See also

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