Check if a given key already exists in a dictionary?

Question

I wanted to test if a key exists in a dictionary before updating the value for the key.I wrote the following code: if 'key1' in dict.keys(): print "blah" else: print "boo"I think this is not the best way to accomplish this task. Is there a better way to test for a key in the dictionary?

Answer 1

If you just want to test whether key k exists in dict d, then

if k in d:

will do the job.

For example,

if k in d:

print('blah')

d[k] = 'new_value'

else:

print('boo')