perl - 你如何降级bigrat？

perl -Mbigrat -E'for (1..100) { $i += 1/3; say int($i), "\t", sprintf "%.55f", $i }'

垃圾邮件有很多警告:

Argument "100/3" isn't numeric in addition (+) at …/site_perl/5.24.1/Math/BigRat.pm line 1939.

在没有-Mbigrat的情况下再次运行，以查看sprintf的预期效果。

您如何将 Math::BigRat 实例$i降级为可转换为sprintf的普通NV？

版本:

bigrat 0.47

Math::BigRat 0.2612

最佳答案

我期望Math::BigRat提供一种获取纯数字的方法，它可以:

整数的as_int

float 的as_float

我插入了$_的打印内容以进行调试。
$i->as_int()与int($i)相同:

$ perl -Mbigrat -E'for (1..100) { $i += 1/3; say $_, "\t", int($i), "\t", sprintf "%.55f", $i->as_int() }'
...
99      33      33.0000000000000000000000000000000000000000000000000000000
100     33      33.0000000000000000000000000000000000000000000000000000000

$i->as_float()乍一看似乎可以正常工作，但我不明白输出结果。所有小数位均为零，每第二行$i等于$_:

$ perl -Mbigrat -E'for (1..100) { $i += 1/3; say $_, "\t", int($i), "\t", sprintf "%.55f", $i->as_float() }'
...
90      30      30.0000000000000000000000000000000000000000000000000000000
91      30      91.0000000000000000000000000000000000000000000000000000000
92      30      92.0000000000000000000000000000000000000000000000000000000
93      31      31.0000000000000000000000000000000000000000000000000000000
94      31      94.0000000000000000000000000000000000000000000000000000000
95      31      95.0000000000000000000000000000000000000000000000000000000
96      32      32.0000000000000000000000000000000000000000000000000000000
97      32      97.0000000000000000000000000000000000000000000000000000000
98      32      98.0000000000000000000000000000000000000000000000000000000
99      33      33.0000000000000000000000000000000000000000000000000000000
100     33      100.0000000000000000000000000000000000000000000000000000000

这是带有Math::BigRat 0.2614的Perl 5.30.0。

因此，警告已修复，但此解决方案似乎出了点问题。

更新:如无sprintf的注释中所要求:

$ perl -Mbigrat -E'for (1..100) { $i += 1/3; say $_, "\t", int($i), "\t", $i->as_float() }'
...
90      30      30
91      30      91
92      30      92
93      31      31
94      31      94
95      31      95
96      32      32
97      32      97
98      32      98
99      33      33
100     33      100