temp_stats.kt in Kotlin

A week of temperatures: extremes, mean, a bar chart, and overnight swings.

// Summarize a week of temperature readings: extremes, mean, swings.

import kotlin.math.abs

val READINGS = listOf(
    "Mon" to -4.0, "Tue" to -1.5, "Wed" to 2.0, "Thu" to 3.5,
    "Fri" to 1.0, "Sat" to -2.5, "Sun" to -6.0,
)

fun main() {
    val temps = READINGS.map { it.second }
    val coldest = READINGS.minByOrNull { it.second }!!
    val warmest = READINGS.maxByOrNull { it.second }!!

    println("Coldest: ${coldest.first} at ${coldest.second} C")
    println("Warmest: ${warmest.first} at ${warmest.second} C")
    println("Mean: %.1f C".format(temps.average()))

    // Chart each day against the freezing line.
    for ((day, t) in READINGS) {
        val bar = "#".repeat((t + 7).toInt().coerceAtLeast(1))
        val side = if (t > 0) "above" else "below"
        println("%-4s %5.1f %s %s".format(day, t, bar, side))
    }

    val swings = temps.zipWithNext { a, b -> b - a }
    println("Sharpest overnight swing: %.1f C".format(
        swings.maxOf { abs(it) }))
}

How it works

1. minByOrNull and maxByOrNull find the cold and warm records.
2. The loop destructures each day and charts it against freezing.
3. zipWithNext pairs neighbors; maxOf with abs finds the sharpest swing.

Keywords and builtins used here

• else
• for
• fun
• if
• import
• in
• it
• main
• val

The run, in numbers

Lines

29

Characters to type

903

Tokens

252

Three-star pace

65 tpm

At the three-star pace of 65 tokens a minute, this run takes about 233 seconds.

Type this snippet

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

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