<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Oct 5, 2016, at 2:30 AM, Lars-Jørgen Kristiansen via swift-users <<a href="mailto:swift-users@swift.org" class="">swift-users@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="" style="font-family: Alegreya-Regular; font-size: 15px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div class="" style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(39, 42, 216);"><div class="" style="margin: 0px; line-height: normal; color: rgb(0, 132, 0);"><span class="" style="font-variant-ligatures: no-common-ligatures;">// Also noticed this:</span></div><div class="" style="margin: 0px; line-height: normal; color: rgb(79, 129, 135);"><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(209, 47, 27);">"</span><span class="" style="font-variant-ligatures: no-common-ligatures;">\</span><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(209, 47, 27);">(</span><span class="" style="font-variant-ligatures: no-common-ligatures;">floatNumber</span><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(209, 47, 27);">)"</span><span class="" style="font-variant-ligatures: no-common-ligatures;"><span class="Apple-converted-space"> </span></span><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(0, 132, 0);">// "1e+07"</span></div><div class="" style="margin: 0px; line-height: normal; color: rgb(0, 132, 0);"><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(209, 47, 27);">"</span><span class="" style="font-variant-ligatures: no-common-ligatures;">\</span><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(209, 47, 27);">(</span><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(79, 129, 135);">doubleNumer</span><span class="" style="font-variant-ligatures: no-common-ligatures; color: rgb(209, 47, 27);">)"</span><span class="" style="font-variant-ligatures: no-common-ligatures;"><span class="Apple-converted-space"> </span></span><span class="" style="font-variant-ligatures: no-common-ligatures;">// "10000000"</span></div></div></div></div></blockquote></div><br class=""><div class="">Numbers around 10 million are too large to be represented exactly by a 32-bit float — the mantissa is 24 bits, including sign, so its range is ±8.3 million. (The specific number 10,000,000 does come out exactly, though, since it’s a multiple of 128.) </div><div class=""><br class=""></div><div class="">So even if Float.description did use non-scientific notation for numbers at this scale, they wouldn’t be accurate. In fact the implementor of the .description method may have decided intentionally to switch to scientific notation at this scale so that the number of significant figures can be limited to the available precision.</div><div class=""><br class=""></div><div class="">—Jens</div></body></html>