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Dictionary

my_dict = dict()
my_dict = {}

Set Item O(1) -> O(n)

my_dict[key] = value

Get Item O(1) -> O(n)

my_dict[key] # Returns the item with the key, KeyError is not in dict
my_dict.get(key[, default]) # Returns the value for the key if in the dictionary
                 # Otherwise the provided default or None if not provided

Set Item Pattern

for i in my_dict:
  # if key is not present then it genrate error, or if first time 
  # key come then it generate error and goto except block
  # so initilize char with 1 value
  try:
      my_dict[i] += 1
  except:
      my_dict[i] = 1

Dict Views

Items
for key, val in my_dict.items():
  print(key, val)
if (key, value) in my_dict.items() # Check if (key, value) tuple in dict
Keys
for key in my_dict.keys()
  print(key)
if key in my_dict.keys() # Check if key in keys
Values
for val in my_dict.values()
  print(val)
if val in my_dict.values() # Check if val in values

Delete Item O(1) -> O(n)

del my_dict[key]

Check in Dict

key in my_dict # True if my_dict has a key, else False
key not in my_dict 

Size

len(my_dict)

Clear

my_dict.clear()