The first two issues of the serialization:
Python string detailed knowledge points to explain the attached code [learn Python from 0 to 1]
What is the method of Python list, with the actual case source code
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<1> Viewing elements
In addition to using key to find data, you can also use get to get data
demo:
info = {
'name':'乐搏学院','age':18}
print(info['name']) # 获取名字
结果：乐搏学院
# print(info['sex']) # 获取不存在的key，会发生异常
print(info.get('sex')) # 获取不存在的key，获取到空的内容，不会出现异常
<2> Modify elements
The data in each element of the dictionary can be modified, as long as the key is found, the
demo can be modified:
info = {
'name':'班长', 'id':100, 'sex':'f', 'address':'地球亚洲中国北京'}
newId = input('请输入新的学号')
info['id'] = int(newId)
print('修改之后的id为%d:'%info['id'])
<3> Add element
demo: access non-existing elements
info = {
'name':'班长', 'sex':'f', 'address':'地球亚洲中国北京'}
print('id为:%d'%info['id'])
如果在使用 变量名['键'] = 数据 时，这个“键”在字典中，不存在，那么就会新增这个元素
demo:添加新的元素
info = {
'name':'班长', 'sex':'f', 'address':'地球亚洲中国北京'}
# print('id为:%d'%info['id'])#程序会终端运行，因为访问了不存在的键
newId = input('请输入新的学号')
info['id'] = newId
print('添加之后的id为:%d'%info['id'])
Result:
Please enter the new student number 188.
The added id is: 188
<4> Delete elements
There are the following types of operations to delete the dictionary:
del
clear()
demo:del删除指定的元素
info = {
'name':'班长', 'sex':'f', 'address':'地球亚洲中国北京'}
print('删除前,%s'%info['name'])
del info['name']
print('删除后,%s'%info['name'])
demo:del删除整个字典
info = {
'name':'monitor', 'sex':'f', 'address':'China'}
print('删除前,%s'%info)
del info
print('删除后,%s'%info)
demo:clear清空整个字典
info = {
'name':'monitor', 'sex':'f', 'address':'China'}
print('清空前,%s'%info)
info.clear()
print('清空后,%s'%info)