python--文件操作/异常捕获/继承
一、文件操作
spath="D:/test/baa.txt" #设置spath值为路径
f=open(spath,"w") #以写的权限打开文件夹，此时baa.txt不存在。
f.write("First line 1.\n")#写入First line 1 回车
f.writelines("First line 2.")+#向此前已打开的文本文件尾追加一行数据.
f.close()#关闭文件操作
f=open(spath,"r") # 以读权限打开文件
for line in f:
??? print line
f.close()
?
?
运行结果：
First line 1.
First line 2.
?
二、异常捕获
s=raw_input("Input your age:")
if s =="":
??? raise Exception("Input must no be empty.")
try:
??? i=int(s)
except ValueError:
??? print "Could not convert data to an integer."
except:
??? print "Unknown exception!"
else: # It is useful for code that must be executed if the try clause does not raise an exception
??? print "You are %d" % i," years old"
finally: # Clean up action
??? print "Goodbye!"
?
运行结果：
Input your age:ad
Could not convert data to an integer.
Goodbye!
?
三、继承
?
class Base:
??? def __init__(self):
??????? self.data = []
??? def add(self, x):
??????? self.data.append(x)
??? def addtwice(self, x):
??????? self.add(x)
??????? self.add(x)
# Child extends Base
class Child(Base):
??? def plus(self,a,b):
??????? return a+b
oChild =Child()
oChild.add("str1")
print oChild.data
print oChild.plus(2,3)
?
?
运行结果：
['str1']
5
?
