Examples

Syntax

e = {}                                        # empty dict
d = {'key1': 'value1', 'key2': 'value2'}      # flat "hash"
n = {'toplevelkey': { 'subkey1': 'value3' }}  # nested "hash"

print(d)
print(len(d))                  # return length

Access dictionaries using []

d['key1']                      # gives 'value1'
n['toplevelkey']['subkey1']    # gives 'value3'

Adding and removing stuff

d['key3'] = 'abc'                 # adds new key
del n['toplevelkey']['subkey1']   # delete a sub key

Testing for keys

if 'key1' in d:
     print("Key exists.")

Iterating

To iterate on keys:
for k in d:
     print("key=", k)
To iterate on tuples:
for k, v in d.items():
    print("key=%s value=%s" % (k,v))