Python：从json文件中获取特定键的所有值

Question

Im getting the json data from a file:

 "students": [
     {
        "name" : "ben",
        "age" : 15
     },
     {
        "name" : "sam",
        "age" : 14
     }
  ]
}

here's my initial code:

def get_names():
  students = open('students.json')
  data = json.load(students)

I want to get the values of all names

[ben,sam]

Answer 1

you need to extract the names from the students list.

data = {"students": [
     {
        "name" : "ben",
        "age" : 15
     },
     {
        "name" : "sam",
        "age" : 14
     }
  ]
       }

names = [each_student['name'] for each_student in data['students']]

print(names) #['ben', 'sam']

Answer 2

Try using a list comprehension:

>>> [dct['name'] for dct in data['students']]
['ben', 'sam']
>>> 

Answer 3

import json
with open('./students.json', 'r') as students_file:
    students_content = json.load(students_file)
print([student['name'] for student in students_content['students']]) # ['ben', 'sam']

Answer 4

JSON's load function from the docs :

Deserialize fp (a .read()-supporting text file or binary file containing a JSON document) to a Python object...

The JSON file in students.json will look like:

{
    "students": [
        {
        "name" : "ben",
        "age" : 15
        },
        {
        "name" : "sam",
        "age" : 14
        }
    ]
}

The JSON load function can then be used to deserialize this JSON object in the file to a Python dictionary:

import json

# use with context manager to ensure the file closes properly
with open('students.json', 'rb')as students_fp:
    data = json.load(students_fp)

print(type(data))  # dict i.e. a Python dictionary

# list comprehension to take the name of each student
names = [student['name'] for student in data['students']]

Where names now contains the desired:

["ben", "sam"]