python语法_类和语句
目录
python类
类的init函数
#类定义
class people:
#定义基本属性
name = ''
age = 0
#定义私有属性,私有属性在类外部无法直接进行访问
__weight = 0
#定义构造方法
def __init__(self,n,a,w):
self.name = n
self.age = a
self.__weight = w
def speak(self):
print("%s 说: 我 %d 岁。" %(self.name,self.age))
# 实例化类
p = people('runoob',10,30)
p.speak()
类继承
#定义父类:Parent
class Parent(object):
def __init__(self, name):
self.name = name
print("create an instance of:", self.__class__.__name__)
print("name attribute is:", self.name)
#定义子类Child ,继承父类Parent
class Child(Parent):
pass
#子类实例化时,由于子类没有初始化,此时父类的初始化函数就会默认被调用
#且必须传入父类的参数name
c = Child("init Child")
print(c.name)
super父类初始化
python语句
encoding标头
#coding:utf-8
try-exception
try:
cql_node = match_sql + r_sql + where_sql + return_sql
node = self.graph.run(cql_node).data()
except Exception:
print('[ERROR] cant get node from neo4j!')
traceback.print_exc()
else:
return node
三目运算符
a = 10
9 if a>8 else 10
out: 9
match=('teacher'
if len(node_type)!=0 else 'hi')
赋值时必须有括号;
for语句创建dict
from collections import defaultdict
type_corners = {ltype:defaultdict(set) for ltype in useful_types}
type_corners:
{1: defaultdict(set, {}),
2: defaultdict(set, {}),
3: defaultdict(set, {}),
4: defaultdict(set, {})}
enumerate语句
for i, homo_att in enumerate(self.HomoAttModels):
其他
traceback打印语句
traceback.print_exc()