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丸め.四捨五入（Round）

Python​

py
round(f, n)

Swift​

swift
f.round(.toNearestOrAwayFromZero)
FloatingPointRoundingRule動作Excel でいう
.awayFromZero0 から遠い方へRoundUp
.down切り捨てFloor
.toNearestOrAwayFromZero四捨五入Round
.toNearestOrEven0.5 は偶数へ-
.towardZero0 に近い方へRoundDown
.up切り上げCeil
swift
for n in -30...30 {
    let f = Double(n) / 10.0

    var v = [f]

    for r: FloatingPointRoundingRule in [
        .down,
        .awayFromZero,
        .toNearestOrAwayFromZero,
        .toNearestOrEven,
        .towardZero,
        .up,
    ] {
        v.append(f.rounded(r))
    }
    print(v)
}

TypeScript​

ts
Math.round(f)

Bash​

bash
printf '%.1f' $v  # ただし 123.05 は 123.0 になるようだ

Ruby​

rb
f.round(n)

Excel​

txt
=ROUND(数値, 桁数)