关于python:Python-入门系列-22-dict-的基本操作详解

拜访字典中的项

能够应用 [key] 的形式来拜访字典中的项，比方获取上面字典中的 key=model 的值，代码如下：

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

PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
Mustang

当然除了中括号，还能够应用 get() 办法来拜访，如下代码所示:

x = thisdict.get("model")

获取字典中的所有 keys

要想获取字典中的所有 keys，能够间接调用 dict 的 keys() 办法即可。

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

PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
dict_keys(['brand', 'model', 'year'])

获取字典中的所有 values

除了能够获取 dict 中的 keys，还能够通过 values() 获取 dict 中的所有 value，如下代码所示：

thisdict = {
  "brand": "Ford",
  "model": "Mustang",
  "year": 1964
}
keys = thisdict.values()

print(keys)

PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
dict_values(['Ford', 'Mustang', 1964])

获取字典中的每一项

下面的办法别离从 dict 中获取 keys 或者 values, 这一节咱们调用 items() 获取字典中的 key-value 汇合，如下代码所示:

thisdict = {
  "brand": "Ford",
  "model": "Mustang",
  "year": 1964
}

items= thisdict.items()

print(items)

PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
dict_items([('brand', 'Ford'), ('model', 'Mustang'), ('year', 1964)])

查看字典中是否存在指定 key

要想判断字典中是否存在某一个 key，能够用 python 内置的 in 操作符即可，如下代码所示：

thisdict = {
  "brand": "Ford",
  "model": "Mustang",
  "year": 1964
}
if "model" in thisdict:
  print("Yes,'model'is one of the keys in the thisdict dictionary")

PS E:\dream\markdown\python> & "C:/Program Files (x86)/Python/python.exe" e:/dream/markdown/python/app/app.py
Yes, 'model' is one of the keys in the thisdict dictionary

译文链接：https://www.w3schools.com/pyt…