pyrand is an implementation of a pseudo-random number generator (PRNG) with the explicit goal that when seeded with identical values, it generates the same numbers as the default implementation in the CPython 2 standard library, including support for seeding with arbitrarily large integers (via the math/big package), however not (yet) for generating arbitrarily large random numbers. The stress is on the "2": The PRNGs in Python 2 and 3 don't behave 100% identically.
This is a fairly narrow use case; if you don't care about it, then this PRNG probably won't give you anything that other implementations don't, including Go's built-in one. In particular, it is a Mersenne Twister, and thus is not cryptographically secure. Don't use it to generate SSH keys.
The only reason that I created this was that when porting Unicornify, I wanted it to be backwards compatible with the original Python implementation (i.e. when given the same hash, it should generate the same unicorn that the original did).
pyrand provides a single type, Random. A newly created Random is unseeded and thus useless; there is no auto-seeding because the only point of this implementation is that it predictably gives the same number sequences as Python when seeded identically. So the first thing you should do is seed the Random:
r := NewRandom()
r.SeedFromUInt32(12345)
Note that a Random is inherently mutable
The following seeding methods are provided. They take numbers in various representations and will cause the Random to generate the same values as a Python 2 random.Random seeded with the same number. The argument to SeedFromBytes is interpreted as big-endian (most significant byte first). In contrast, the argument to SeedFromUInt32s (around which all the others are essentially wrappers) interprets it as little-endian (least significant uint32 first).
SeedFromUInt32(uint32)
SeedFromUInt64(uint64)
SeedFromBig(*big.Int)
SeedFromHexString(string)
SeedFromBytes([]byte)
SeedFromUInt32s([]uint32)
The following methods to retrieve random numbers are provided, and they mimic the correspondingly named Python methods. Note that, unlike the Python version, RandRange takes no step parameter.
Random() float64
RandBits(uint) []uint32
RandInt(int, int) int
RandRange(int, int) int
See the method documentations for more details.
See the accompanying file LICENSE.txt for copyright and licensing information.