创建NumPy数组并将其另存为Django上下文变量后,加载网页时出现以下错误:
array([ 0, 239, 479, 717, 952, 1192, 1432, 1667], dtype=int64) is not JSON serializable
这是什么意思?
我定期“ jsonify” np.arrays。尝试首先在数组上使用“ .tolist()”方法,如下所示:
import numpy as np import codecs, json a = np.arange(10).reshape(2,5) # a 2 by 5 array b = a.tolist() # nested lists with same data, indices file_path = "/path.json" ## your path variable json.dump(b, codecs.open(file_path, 'w', encoding='utf-8'), separators=(',', ':'), sort_keys=True, indent=4) ### this saves the array in .json format
为了“ unjsonify”数组使用:
obj_text = codecs.open(file_path, 'r', encoding='utf-8').read() b_new = json.loads(obj_text) a_new = np.array(b_new)
将numpy.ndarray或任何嵌套列表组合作为JSON存储。
class NumpyEncoder(json.JSONEncoder): def default(self, obj): if isinstance(obj, np.ndarray): return obj.tolist() return json.JSONEncoder.default(self, obj) a = np.array([[1, 2, 3], [4, 5, 6]]) print(a.shape) json_dump = json.dumps({'a': a, 'aa': [2, (2, 3, 4), a], 'bb': [2]}, cls=NumpyEncoder) print(json_dump)
将输出:
(2, 3) {"a": [[1, 2, 3], [4, 5, 6]], "aa": [2, [2, 3, 4], [[1, 2, 3], [4, 5, 6]]], "bb": [2]}
要从JSON还原:
json_load = json.loads(json_dump) a_restored = np.asarray(json_load["a"]) print(a_restored) print(a_restored.shape)
[[1 2 3] [4 5 6]] (2, 3)