Python for and if-else One line syntax [duplicate]

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• How can I do assignments in a list comprehension? 3 answers

I want to convert following code to one line code

pos, neg=0,0
for val in price_changes:
        if val >0:
            pos+=val
        else:
            neg+=val

Converted to

pos, neg=0,0
pos+=val if val>0 else neg+=val for val in price_changes

But it gives syntax error

SyntaxError: invalid syntax

Where I am wrong