Powershell bigint 输出与声明值不同
Powershell bigint output differ from declared value
我正在将 lesspass 密码管理器移植到 powershell，但是我在实施 _consume_entropy() method 时遇到了问题，尤其是 Python divmod.
转载
PS> [bigint]$EntropyAsInt = 99600400399777174105034830393873797761817714609490038944205586760025858632478
PS> Write-Host $EntropyAsInt
99600400399777173995117538344184441997741701018199539534149245151907290284032
差异
99600400399777174105034830393873797761817714609490038944205586760025858632478
99600400399777173995117538344184441997741701018199539534149245151907290284032
^ start diverging he
问题
这是怎么回事？我用错类型了吗？
我可以复制该行为，但无法解释。我可以 做的是为您提供解决方法。将变量定义为 [bigint]，然后将您的号码解析为引用先前创建的变量的字符串。
[bigint]$EntropyAsInt=0
[bigint]::TryParse('99600400399777174105034830393873797761817714609490038944205586760025858632478',[ref]$EntropyAsInt)
然后您可以验证 $EntropyAsInt 是否包含您之前指定的号码。
感谢 Joel 在 Powershell slack 上的表现：
The issue is that the bigint cast doesn't take effect until after the value is parsed. It will first be parsed as a double, which in where the imprecision occurs
If you want it to retain the exact number, you need to put your literal in quotes to make it a string and have the cast itself do the parsing
[bigint]$var = "12345342827266162738883736363"
工作正常
[bigint]$EntropyAsInt = "99600400399777174105034830393873797761817714609490038944205586760025858632478"
99600400399777174105034830393873797761817714609490038944205586760025858632478 是 [Double]...
PS> 99600400399777174105034830393873797761817714609490038944205586760025858632478
9.96004003997772E+76
PS> (99600400399777174105034830393873797761817714609490038944205586760025858632478).ToString("F0")
99600400399777200000000000000000000000000000000000000000000000000000000000000
PS> (99600400399777174105034830393873797761817714609490038944205586760025858632478).GetType()
IsPublic IsSerial Name BaseType
-------- -------- ---- --------
True True Double System.ValueType
当它转换为 [BigInt] 时，原始值已经丢失。以 [String] 开头会保留它，但是...
PS> [bigint]$EntropyAsInt = '99600400399777174105034830393873797761817714609490038944205586760025858632478'
PS> $EntropyAsInt
99600400399777174105034830393873797761817714609490038944205586760025858632478
有关详细信息，请参阅 Instantiating a BigInteger Object。
我正在将 lesspass 密码管理器移植到 powershell，但是我在实施 _consume_entropy() method 时遇到了问题，尤其是 Python divmod.
转载
PS> [bigint]$EntropyAsInt = 99600400399777174105034830393873797761817714609490038944205586760025858632478
PS> Write-Host $EntropyAsInt
99600400399777173995117538344184441997741701018199539534149245151907290284032
差异
99600400399777174105034830393873797761817714609490038944205586760025858632478
99600400399777173995117538344184441997741701018199539534149245151907290284032
^ start diverging he
问题
这是怎么回事？我用错类型了吗？
我可以复制该行为，但无法解释。我可以 做的是为您提供解决方法。将变量定义为 [bigint]，然后将您的号码解析为引用先前创建的变量的字符串。
[bigint]$EntropyAsInt=0
[bigint]::TryParse('99600400399777174105034830393873797761817714609490038944205586760025858632478',[ref]$EntropyAsInt)
然后您可以验证 $EntropyAsInt 是否包含您之前指定的号码。
感谢 Joel 在 Powershell slack 上的表现：
The issue is that the bigint cast doesn't take effect until after the value is parsed. It will first be parsed as a double, which in where the imprecision occurs
If you want it to retain the exact number, you need to put your literal in quotes to make it a string and have the cast itself do the parsing
[bigint]$var = "12345342827266162738883736363"
工作正常
[bigint]$EntropyAsInt = "99600400399777174105034830393873797761817714609490038944205586760025858632478"
99600400399777174105034830393873797761817714609490038944205586760025858632478 是 [Double]...
PS> 99600400399777174105034830393873797761817714609490038944205586760025858632478
9.96004003997772E+76
PS> (99600400399777174105034830393873797761817714609490038944205586760025858632478).ToString("F0")
99600400399777200000000000000000000000000000000000000000000000000000000000000
PS> (99600400399777174105034830393873797761817714609490038944205586760025858632478).GetType()
IsPublic IsSerial Name BaseType
-------- -------- ---- --------
True True Double System.ValueType
当它转换为 [BigInt] 时，原始值已经丢失。以 [String] 开头会保留它，但是...
PS> [bigint]$EntropyAsInt = '99600400399777174105034830393873797761817714609490038944205586760025858632478'
PS> $EntropyAsInt
99600400399777174105034830393873797761817714609490038944205586760025858632478
有关详细信息，请参阅 Instantiating a BigInteger Object。