python3.x 基础四：json与pickple

Posted 2020-10-15 不懂ABAP的python不是好basis

• 每次打开一个文件，只dump1次
• json.dump(dump的内容，文件句柄)
• json.load(文件句柄)
• json可以处理列表/字典/字符串等简单数据类型，但是不能处理复杂的数据类型，如函数的内存地址
• 不同语言间都可以用json文件

import json
dict1={‘name‘:‘alex‘,‘age‘:22,‘salary‘:1000}
print(‘dict is %s\ndumping dict to file...‘ % (dict1))
fd = open(‘fd.txt‘,‘w‘,encoding=‘utf-8‘)
# with open(‘fd.txt‘,‘w‘,encoding=‘utf-8‘) as fd:
#     json.dump(dict1,fd)
dict2={‘name‘:‘oldboy‘,‘age‘:32,‘salary‘:2000}
# with open(‘fd.txt‘,‘w‘,encoding=‘utf-8‘) as fd:
#     json.dump(dict2,fd)
json.dump(dict1,fd)
fd.close()
# json.dump(dict2,fd)
fd = open(‘fd.txt‘,‘r‘,encoding=‘utf-8‘)
print(‘load content from file...‘)
print(json.load(fd))
fd.close()
output：
dict is {‘age‘: 22, ‘salary‘: 1000, ‘name‘: ‘alex‘}
dumping dict to file...
load content from file...
{‘age‘: 22, ‘salary‘: 1000, ‘name‘: ‘alex‘}
dumping dict to file...

import json
dict1={}
def func():
    print(‘in the func‘)
dict1[‘name‘]=func
fd = open(‘fdw.txt‘,‘w‘,encoding=‘utf-8‘)
print(‘dumping dict to file...‘ % (dict1))
json.dumps(dict1,fd)
fd.close()
error：
TypeError: <function func at 0x7f0828c68488> is not JSON serializable

• pickle能处理python所有的数据类型

import pickle
dict1={}
def func():
    print(‘in the func‘)
dict1[‘name‘]=func
fd = open(‘fdw.txt‘,‘wb‘)
print(‘dumping dict to file... %s‘ % (dict1))
pickle.dump(dict1,fd)
fd.close()
fd = open(‘fdw.txt‘,‘rb‘)
print(pickle.load(fd))
fd.close()
output：
dumping dict to file... {‘name‘: <function func at 0x7fa1904d4488>}
{‘name‘: <function func at 0x7fa1904d4488>}