劉任昌python字典dictionaries

w3schools截圖

w3schools程式碼

#劉任昌 字典 keys:value市場價值最大的公司
a =	{
  2330: "台積電", 2317: "鴻海",
  2454: "聯發科", 2412: "中華電", 
  6505:"台塑化",2308: "台達電"}
print(a)
print("迴圈列出字典的所有值")
for t in a:
   print(a[t])
b = a.copy() #字典不能直接assign
print(b)
a.update({2881:"富邦金控"})#台灣第七大
a.update({2303:"聯電"})    #台灣大八大
for t in a:
   print(a[t])
a.setdefault(1303,"南亞")
a.setdefault(2882,"國泰金")
i = 0
for t in a: #python迴圈不使用{...}縮排整齊整齊
   i = i + 1
   print("台灣第" + str(i) + a[t])

w3schools字典方法列表

Python has a set of built-in methods that you can use on dictionaries.

Method	Description
clear()	移除字典內容Removes all the elements from the dictionary
copy()	拷貝Returns a copy of the dictionary
fromkeys()	Returns a dictionary with the specified keys and value
get()	取得鍵Returns the value of the specified key
items()	Returns a list containing a tuple for each key value pair
keys()	Returns a list containing the dictionary's keys
pop()	移除Removes the element with the specified key
popitem()	Removes the last inserted key-value pair
setdefault()	Returns the value of the specified key. If the key does not exist: insert the key, with the specified value
update()	Updates the dictionary with the specified key-value pairs
values()	Returns a list of all the values in the dictionary

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