temp_stats.exs in Elixir

A week of daily highs reduced to low, high and mean, with a scaled bar per day.

# One week of daily highs: spread, mean, and a scaled bar chart.
week = [
  {"Mon", 61}, {"Tue", 68}, {"Wed", 74}, {"Thu", 79},
  {"Fri", 72}, {"Sat", 65}, {"Sun", 58}
]

temps = Enum.map(week, fn {_day, t} -> t end)
lo = Enum.min(temps)
hi = Enum.max(temps)
mean = Enum.sum(temps) / length(temps)
span = max(hi - lo, 1)

# Bars scale to the week's spread; the +1 keeps the coolest day visible.
bar = fn t -> String.duplicate("#", 1 + div(20 * (t - lo), span)) end

diff = fn t ->
  shown = Float.round(abs(t - mean), 1)
  if t >= mean, do: "+#{shown}", else: "-#{shown}"
end

IO.puts("day   high  range                  diff")
IO.puts(String.duplicate("-", 40))

for {day, t} <- week do
  IO.puts(
    String.pad_trailing(day, 5) <>
      String.pad_leading(Integer.to_string(t), 4) <> "  " <>
      String.pad_trailing(bar.(t), 21) <>
      String.pad_leading(diff.(t), 5)
  )
end

IO.puts(String.duplicate("-", 40))
IO.puts("low #{lo}, high #{hi}, mean #{Float.round(mean, 1)}")
IO.puts("days above the mean: #{Enum.count(temps, fn t -> t > mean end)}")

How it works

1. Enum.map strips the temps out; Enum.min, Enum.max and a division set the spread.
2. bar scales each day against the spread and diff signs the distance from the mean.
3. The for loop pads each row into columns; the footer counts the days above the mean.

Keywords and builtins used here

• Enum
• Float
• IO
• Integer
• String
• do
• end
• fn
• for
• if

The run, in numbers

Lines

35

Characters to type

1022

Tokens

344

Three-star pace

70 tpm

At the three-star pace of 70 tokens a minute, this run takes about 295 seconds.

Type this snippet

Step 3 of 3 in Encore, step 27 of 27 in Language basics.

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