需要计算偶数位的数字之和。 可能是什么错误？

Question

It is necessary to count the numbers on the even positions. I wrote a function, but I can't figure out what is the error? For example, in the number 55443352, 5 + 4 + 3 + 5 = 17. It was expected to get this.

`def cnt_sum(one):
sum = 0
tmp = one
i=0
while tmp //= 10:
    i = i + 1 
while one:
    if (i==%2 == 0)
        sum +=one%10
        one/=10
return sum

cnt_sum(55443352)`

Please help me figure it out..

while tmp // = 10:
           ^
  SyntaxError: invalid syntax

Answer 1

You can't assign temp there unless you're using the walrus operator (3.8+):

In [98]: while temp = temp // 10:
    ...:     print(temp)
    ...:
  File "<ipython-input-98-38590cf2c5e0>", line 1
    while temp = temp // 10:
               ^
SyntaxError: invalid syntax

With walrus operator:

In [99]: while temp := temp // 10:
    ...:     print(temp)
    ...:
10
1

Otherwise you can do this:

In [99]: while temp:
    ...:     print(temp)
    ...:     temp //= 10
    ...:
100
10
1

Depending where you place the floor operator will depend on whether or not you also get the first value of temp .

Answer 2

Lots of errors in posted code.

Code can be simplfied to:

def cnt_sum(number):
    sum_ = 0                  # don't use sum as a variable name (conflicts with built-in function(
    str_number = str(number)  # number as string
    for i, v in enumerate(str_number):
        # enumerate is Pythonic method for iterating through a list of values with the index
        if i % 2 == 0:
            # We're on an even index
            sum_ += int(v)   # add digit at this index (need int since we have a lit of character digits)
    return sum_

Can be further simplified to

def cnt_sum(number):
    return sum(int(v) for i, v in enumerate(str(number)) if i % 2 == 0)

Output

cnt_sum(55443352)# result is 17