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How to parse big decimal data #2036

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YXQ212526 opened this issue Apr 13, 2020 · 3 comments
Closed

How to parse big decimal data #2036

YXQ212526 opened this issue Apr 13, 2020 · 3 comments
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kind: question solution: proposed fix a fix for the issue has been proposed and waits for confirmation

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@YXQ212526
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Hi nlohmann,
I want to know how to parse data like this:
image
I use the parse () function to parse the original string and use ["data"] [0] ["amount"] to get the value,but I can't get accurate data, what I got is 7.953084699036454 instead of 7.953084699036454431
Looking forward to your reply, thanks!
@nlohmann
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The number 7.953084699036454431 cannot be expressed exactly by a 64 bit double, see https://float.exposed/0x401fcff56f72b7e2. The closest you can get is the number with hex representation 0x401fcff56f72b7e2. For this number, 7.953084699036454 is the shortest decimal representation. Therefore, this is used by the library.

@nlohmann nlohmann added the solution: proposed fix a fix for the issue has been proposed and waits for confirmation label Apr 13, 2020
@nlohmann
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Related issues: #1580 #1698

@YXQ212526
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Thx for your reply 👍

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@nlohmann @YXQ212526