Symbol replacement in python

Question

There's a string: a = 's+4-3'
I need to replace (invert) + with - and - with + to get:
's-4+3'

What is the way of doing that?

Answer 1

print(a.replace('+','.').replace('-','+').replace('.','-'))

Answer 2

Now with two additional realisations. I, personally, like the dictionary variation pretty much as it is most flexible with minimal effort for extension:

a = 's+4-3'
print("Original string: %s" % (a))
swap_a = a.replace('+','.').replace('-','+').replace('.','-')
print("String after swapping operators, procedure (1): %s" % (swap_a))
swap_b = ""
for char in a:
if char == '+':
swap_b += '-'
elif char == '-':
swap_b += '+'
else:
swap_b += char
print("String after swapping operators, procedure (2): %s" % (swap_b))
swapDict = {'+': '-','-': '+'}
swap_c = ''.join(swapDict[char] if char in swapDict else char for char in a)
print("String after swapping operators, procedure (3): %s" % (swap_c))