Use open(file, mode) for files.
The mode is a variant of 'r' for read, 'w' for write, and possibly 'b' appended (e.g., 'rb') to open binary files. See the link below.
Use open with readline() or readlines(). The former will return a line at a time, while the latter returns a list of the lines.
Use split(delimiter) to split on the comma.
Lastly, you need to cast each item to an integer: int(foo). You'll probably want to surround your cast with a try block followed by except ValueError as in the link below.
You can also use 'multiple assignment' to assign a and b at once:
>>>a, b = map(int, "2342342,2234234".split(","))
>>>print a
2342342
>>>type(a)
<type 'int'>