Dictionary

store data values in key:value pairs

• 3.7 > ordered (the items have a defined order, and that order will not change.)
• changeable
• does not allow duplicates

thisdict = {
  "brand": "Ford",
  "model": "Mustang",
  "year": 1964
}
print(thisdict["brand"])

len()

type()

< class 'dict'>

Access

1. []
2. get()

x = thisdict.get("model")

3. keys() - return a list of all the keys

Note

The list of the keys is a view of the dictionary, meaning that any changes done to the dictionary will be reflected in the keys list.

4.values()

Note

The list of the values is a view of the dictionary, meaning that any changes done to the dictionary will be reflected in the values list.

5.items() - return each item in a dictionary, as tuples in a list.

Note

The returned list is a view of the items

exist

if in

Change Item

1. thisdict["year"] = 2018
2. thisdict.update({"year": 2020})

Add Item

1. []

thisdict = {
  "brand": "Ford",
  "model": "Mustang",
  "year": 1964
}
thisdict["color"] = "red"

2. update() - if the item does not exist, the item will be added.

thisdict.update({"color": "red"})

Remove Items

1.pop("key") 2.popitem() - remove the last inserted item( bef. 3.7 a random item removed) 3.del thisdict["model"]

Note

can also delete the dictionary completely

del thisdict

4.clear() - empties the dict

Loop

for in

1. for x in thisdict: - all key names
2. for x in thisdict.values(): - all values
3. for x in thisdict.keys(): - through all keys
4. for x, y in thisdict.items() - keys and values

Copy a Dict

cannot dict2 = dict1 => it will reference

1. copy()

mydict = thisdict.copy()

2.dict()

mydict = dict(thisdict)

Nested Dicts

child1 = {
  "name" : "Emil",
  "year" : 2004
}
child2 = {
  "name" : "Tobias",
  "year" : 2007
}
child3 = {
  "name" : "Linus",
  "year" : 2011
}

myfamily = {
  "child1" : child1,
  "child2" : child2,
  "child3" : child3
}

Methods

Dict Methods