错误无法将序列乘以'float'类型的非整数

Question

I'm getting the following error:

     if len(new_send_times) > rate_limit * window * self._throttle:
        TypeError: can't multiply sequence by non-int of type 'float'

This is the code:

if len(new_send_times) > rate_limit * window * self._throttle:
                    # Sleep the remainder of the window period.
                    delta = now - new_send_times[0]
                    total_seconds = (delta.microseconds + (delta.seconds +
                                                           delta.days * 24 * 3600) * 10 ** 6) / 10 ** 6
                    delay = window - total_seconds
                    if delay > 0:
                        sleep(delay)

                recent_send_times.append(now)
                # end of throttling

the values it uses are

if len([]) > 1.0 * 2.0 * 0.5:

Update: I changed it to below and it works, but I still don't understand the error or if want I'm doing it correct:

 if len(new_send_times) > float(rate_limit) * float(window) * float(self._throttle):

Answer 1

The error is pretty self-explonatory. You are performing operation in the form

list * float # or other sequence * float

which is forbidden in python, you can

numeric * float # "traditional" multiplication

or

list * int # creates concatenated copies of the list provided

So investigate your code, check which object is a list and convert it to the number, as the code logic suggests that this is your intended behaviour.

Examples:

[1] * 3 = [1,1,1]

[1] * 1.5 # ERROR

1 * 1.5 == 1.5

float([1]) * 1.5 == 1.5

"1" * 1.5 # ERROR

float("1") * 1.5 == 1.5

Answer 2

The error message

TypeError: can't multiply sequence by non-int of type 'float'

tells you that at least one of

len(new_send_times), rate_limit, window, self._throttle

is not a number, as you suspect, but some kind of sequence.

The fact that you print these values and see what you expect, along with the fact that using float() on the values makes the code work, suggests strongly that one of them is a string representation of a number (eg '1.0' ) rather than the number itself - str in Python counts as a sequence .

len() will always return an int (or raise an error!), so there's no need to worry about that, but one of the other three is probably a string. You need to source where the values are coming from ( [raw_]input ? Parsed file?) and make sure they're being converted to numerical types at the appropriate point (the earlier the better, as in other contexts you may get more subtle problems).

To tell the difference, when print ing the values to check, you could do eg

print(rate_limit, type(rate_limit))