# Reflection ： Used the form of string to manipulate object members （python Everything is an object , So you can also manipulate classes , modular ）
"""
1、getattr(obj, str), Go to obj Object acquisition str attribute , Get the members of the object in the form of a string （ Field , Method ）
2、hasattr（obj, str） testing obj Is there any str member , Return value True or False
3、setattr(obj, key, value), Set up obj Object members ,key=value
4、delattr(obj, str) Delete obj Object members
"""
# Example 1. Operation example object
class Foo1:
def __init__(self, name, age):
self.name = name
self.age = age
def bar(self):
return self.name
foo1 = Foo1('abc', '18')
# We can go through getattr To take a value ,getattr(foo1, b) Indicates that I want to take variables from the object b Value （name） Corresponding field
# This enables a simple interaction , Through the information entered by the user , Find object fields
b = 'name'
print(getattr(foo1, b))
inp = input(' Please enter the fields to query ：') # You need to enter the object member name , If there is no such member, an error will be reported , Use try Capture exception
try:
print(getattr(foo1, inp))
except Exception as e:
print(' The object you are looking for does not exist ')
# adopt getattr Take out the object method
fun = getattr(foo1, 'bar')
print(fun())
# adopt hasattr Determine whether the member exists in the object , return true perhaps False
print(hasattr(foo1, 'name'))
print(hasattr(foo1, 'abc'))
# By setting object members
setattr(foo1, 'abc', '123')
# print(foo1.abc)
# adopt delattr Delete object members , An error will be reported when the value is deleted , adopt try Handling exceptions
delattr(foo1, 'name')
try:
print(foo1.name)
except Exception as e:
print(e)
# Example 2、 Operation class
class Foo2:
name = 'abc'
age = '18'
pass
# Value
print(getattr(Foo2, 'name'))
# Judge whether it exists
print(hasattr(Foo2, 'name'))
print(hasattr(Foo2, 'abc'))
# Set up
setattr(Foo2, 'abc', '123')
print(Foo2.abc)
# Delete , An error will be reported when the value is deleted , adopt try Handling exceptions
delattr(Foo2, 'name')
try:
print(Foo2.name)
except Exception as e:
print(e)
