基本

空の辞書作成

dict = {}

辞書への値追加

dict["dog"]="pochi"

辞書のキー取得

dict.keys()

>>> dict["dog"]="pochi"
>>> dict["cat"]="tama"
>>> dict.keys()
dict_keys(['dog', 'cat'])

辞書の値の取得

dict.values()

>>> dict.values()
dict_values(['pochi', 'tama'])

ちょっと応用

python 辞書　keyを数字で並び替え

sorted(dict.keys(), key=int)

>>> dict.keys()
dict_keys([1, 2, 3, 4, 100, 50])
>>> sorted(dict.keys(),key=int)
[1, 2, 3, 4, 50, 100]

リストの分類分け(カウント)

>>> dict ={}
>>> list = ["dog","dog","cat","dog"]
>>> for i in list:
...     if i in dict.keys():
...         dict[i] += 1
...     else:
...         dict[i] =  0
...         dict[i] += 1
...
>>> dict
{'dog': 3, 'cat': 1}