题解 | #遍历字典#

import sys

a={
    '<':'less than',
    '==':'equal'
}

print("Here is the original dict:")

for keys in a:
        print('Operator {} means {}.'.format(keys,a.get(keys)))

print('\r')
print('The dict was changed to:')
a.setdefault('>','greater than')
for keys in a:
        print('Operator {} means {}.'.format(keys,a.get(keys)))