python 示例

(Dictionary keys() Method)

keys() method

keys()方法用于获取所有键作为视图对象，该视图对象包含字典的所有键。

Syntax:

句法：

dictionary_name.keys()

Parameter(s):

参数：

  • It does not accept any parameter.
    它不接受任何参数。

Return value:

返回值：

The return type of this method is <class 'dict_keys'>, it returns the keys of the dictionary as view object.

此方法的返回类型为<class'dict_keys'> ，它将字典的键作为视图对象返回。

Example 1:

范例1：

# Python Dictionary keys() Method with Example

# dictionary declaration
student = {
  "roll_no": 101,
  "name": "Shivang",
  "course": "B.Tech",
  "perc" : 98.5
}

# printing dictionary
print("data of student dictionary...")
print(student)

# printing keys
print("keys of student dictionary...")
print(student.keys())

# printing return type of student.keys() Method
print("return type is: ", type(student.keys()))

Output

输出量

data of student dictionary...
{'course': 'B.Tech', 'roll_no': 101, 'perc': 98.5, 'name': 'Shivang'}
keys of student dictionary...
dict_keys(['course', 'roll_no', 'perc', 'name'])
return type is:  <class 'dict_keys'>

If we make any changes in the dictionary, view object will also be reflected, consider the given example,

如果我们在字典中进行任何更改，则视图对象也将得到反映，请考虑给定的示例，

Example 2:

范例2：

# Python Dictionary keys() Method with Example

# dictionary declaration
student = {
  "roll_no": 101,
  "name": "Shivang",
  "course": "B.Tech",
  "perc" : 98.5
}

# printing dictionary
print("data of student dictionary...")
print(student)

# printing keys
print("keys of student dictionary...")
print(student.keys())

# changing a value
student['roll_no'] = 999

# printing dictionary
print("data of student dictionary after update...")
print(student)

Output

输出量

data of student dictionary...
{'course': 'B.Tech', 'roll_no': 101, 'perc': 98.5, 'name': 'Shivang'}
keys of student dictionary...
dict_keys(['course', 'roll_no', 'perc', 'name'])
data of student dictionary after update...
{'course': 'B.Tech', 'roll_no': 999, 'perc': 98.5, 'name': 'Shivang'}

See the output, value of roll_no

看到输出， roll_no的值已更改。