Make all members in a list equal with zero python

I want set the value of all members of a list equal with zero or null.

So if I have a list like this: [member1, member2, member3 ,member4,member5,member6]

How can I set their value to zero or null all at once, so I don't need to assign all one by one. For example to do something like this

for item in [member1, member2, member3 ,member4,member5,member6]:
    item  = ''

why this won't work?