ValueError: not enough values to unpack (expected 3, got 0)

原代码：

#!/usr/local/bin/python3
try:
    import numpy as np
except ImportError:
    print("numpy is not installed")
sizes = [37, 5, 6];
print(sizes[-1]);
result = zip(sizes[:-1], sizes[1:]);
ll = len(result);   #cause error: ll = len(result); TypeError: object of type 'zip' has no len()
print(*result);   # correct deference, output (37, 5) (5, 6)
print("len of result = ", ll);

修改：

#!/usr/local/bin/python3
import copy;
try:
    import numpy as np
except ImportError:
    print("numpy is not installed")
sizes = [37, 5, 6];
print(sizes[-1]);
result = zip(sizes[:-1], sizes[1:]);
tt = copy.deepcopy(result);
tt = tuple(tt);
ll = len(tt);
print("result = ", *result);
print("tuple = ", tt);
print("len of result = ", ll);

运行结果：

6
result =  (37, 5) (5, 6)
tuple =  ((37, 5), (5, 6))
len of result =  2