TypeError: object of type 'numpy.float64' has no len()

TypeError: object of type ‘numpy.float64’ has no len()

$ python -c "import numpy as np; x = np.float64(1.0); len(x)"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
TypeError: object of type 'numpy.float64' has no len()'

Why this happens

NumPy scalar types aren’t sequences and therefore don’t have a length. len() expects a sequence/collection.

Fix

If you intended a sequence, create a 1-D array or list. If you just need the value, avoid len() and use Python’s numeric operations.

Wrong code

import numpy as np
val = np.float64(3.14)
print(len(val))

Fixed code

import numpy as np
val = np.array([3.14])
print(len(val))  # now 1
# or
val = np.float64(3.14)
print(float(val))