serialize, persist, retrieve, and de-serialize a NumPy array as a binary string (any dimension, any dtype); exemplary use case: a web app calculates some result--eg, from a Machine Learning algorithm, using NumPy and the result is a NumPy array; it is efficient to just return that result to rather than persist the array then retrieve it via query

serialize-numpy-array.py

import time
import numpy as NP
from redis import StrictRedis as redis

# a 2D array to serialize
A = 10 * NP.random.randn(10000).reshape(1000, 10)

# flatten the 2D NumPy array and save it as a binary string
array_dtype = str(A.dtype)
l, w = A.shape
A = A.ravel().tostring()

# create a key as a UNIX timestamp w/ array shape appended to end of key delimited by '|'
db = redis(db=0)
key = '{0}|{1}#{2}#{3}'.format(int(time.time()), array_dtype, l, w)

# store the binary string in redis
db.set(key, A)

# retrieve the proto-array from redis
A1 = db.get(key)

# deserialize it 
array_dtype, l, w = key.split('|')[1].split('#')

A = NP.fromstring(A1, dtype=array_dtype).reshape(int(l), int(w))

Thanks man!

from io import BytesIO
import numpy as np


# a 2D array to serialize
A = 10 * NP.random.randn(10000).reshape(1000, 10)
with BytesIO() as b:
      np.save(b, A)
      serialized_A = b.getvalue()

A = np.load(BytesIO(serliazed_A))

import numpy as np
from time import time


def method1():
	A = 10 * np.random.randn(10000).reshape(1000, 10)
	
	start_time = time()

	serialized_A = None
	with BytesIO() as b:
		np.save(b, A)
		serialized_A = b.getvalue()
	ser_end = time()

	A = np.load(BytesIO(serialized_A))
	deser_end = time()

	print("Method1: Ser:%f Des:%f" % ((ser_end - start_time), 
			(deser_end - ser_end)))


def method2():
	A = 10 * np.random.randn(10000).reshape(1000, 10)

	start_time = time()

	l, w = A.shape
	A2 = A.ravel().tostring()
	ser_end = time()

	np.fromstring(A2).reshape(int(l), int(w))
	deser_end = time()

	print("Method2: Ser:%f Des:%f" % ((ser_end - start_time), 
			(deser_end - ser_end)))


if __name__ == "__main__":
	method1()
	method2()

	method1()
	method2()

--------------------------------
Output:
Method1: Ser:0.002921 Des:0.000512
Method2: Ser:0.000008 Des:0.000032
Method1: Ser:0.000217 Des:0.000285
Method2: Ser:0.000007 Des:0.000013

Both the BytesIO and "binary string" methods require making copies of the array, right? Would np.frombuffer instead of np.fromstring be able to load data from Redis without copying?