replace|同时替换

a= 'eeekkksksksk'
print a.replace('e','s').replace('s','k')

#kkkkkkkkkkkk

change={"e":"s","k":'@',"s":"!"}
a_new=''.join(change[i] for i in a)
print(a_new)

'''
sss@@@!@!@!@
'''