I'm executing the following snippet on python 2.7:

```
i=0
j=3
a=['A','B','B','A']
while(a[i]=="A" & i<j):
    #do something

```

And I am getting this error.

> 
> TypeError: unsupported operand type(s) for &: 'str' and 'int'
> 
> 
> 

Any help?