While循环，列表中的双精度数字

Question

How would I produce a while loop, to double and therefore change the numbers in the following list?

Thank you.

numberList = [3, 5, 6, 2, 1, 5, 7, 4]

This was my attempt

numberList = [3, 5, 6, 2, 1, 5, 7, 4]

while numberList == numberList:
    numberList == numberList * 2
    print (numberList)
    break

Answer 1

Although not the best way to solve the problem, this is a way of doing it using a while loop:

numberList = [3, 5, 6, 2, 1, 5, 7, 4]
i=0
while i < len(numberList):
    numberList[i] *= 2
    i += 1

>>> numberList
[6, 10, 12, 4, 2, 10, 14, 8]

Notice that multiplying a list by an integer will output a list repeating the elements, so your attempt actually does something like this:

>>> [1,2,3]*2
[1, 2, 3, 1, 2, 3] 

Answer 2

You can map list with a lambda function to perform the desired function!

numberList= [3, 5, 6, 2, 1, 5, 7, 4]
print map(lambda x:x*2,numberList)