Python入門3-變量2

1.字典（使用花括號定義）

  dairy_section = {}

  dairy_section["breakfast"] = ("break","milk")

  dairy_section["lunch"] = ("noodles","rices","dishes")

  dairy_section["dinner"] = ("porridge","steamed bun")

  讀取時可以使用：

  1）print(dairy_section)：顯示全部的值

  2）dairy_section.get("breakfast")：讀取特定值

  3）從字典中取鍵

     print_keys = dairy_section.keys()

     print_values = dairy_section.values(）

2.引用序列的最後一個元素（元組和列表均屬於序列）

  元組（列表）名稱[-1],依次類推，比如week = ("Sunday","monday","Tuesday")

  可使用print(week[-1])打印出"Tuesday"

3.將序列分片

  1)將元組分片：例如workday = ("Monday","Tuesday","Wednesday","Thursday","Friday")

  print(workday[0:2]),顯示"Monday"，“Tuesday”

  2)將列表分片：例如workday = ["Mondy","Tuesday","Wednesday","Thursday","Friday"]

  print(workday[1:3]),顯示"Tuesday","Wednesday"

  3)將字符分片：例如workday = "from Monday to friday"

  print(workday[2:5]),顯示"om "

4.從列表中彈出元素

  today_times = [2,5,3,6]

  A = today_times.pop(0)

  print(A),顯示2,且print(today_times)時顯示[5,3,6]

5.計算元組、列表或字典的長度

  len(元組名或列表名或字典名)

6.處理集合

  alphabet = ['a','b','b','c','d','e','e']

  alph2 = set(alphabet)

  print(alph2)顯示{'a','b','c','d','e'}