Python中break,return和pass,continue用法区别;python中try except处理程序异常的三种常用方法

Python中break,return和pass,continue用法区别

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#判别条件后的执行。
def func():    
	for i in range(1,11):        
		if i % 2 == 0:            
			continue        #if判断后，跳过continue语句下的表达式。不输出print(i)        
			print(i)
func()

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def func1():
    for i in range(1,11):
            if i % 2 == 0:
                        pass    #pass不做任何操作
                       print(i)
func1()

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def func2():
    for i in range(1,11):
            if i % 2 == 0:
            	break        #到第一个符合条件的情况下就停止。不输出符合条件的语句，并停止。
                print(i)
func2()

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def func3():
   for i in range(1,11):
          if i % 2 == 0:
                      return i    #符合第一个条件的语句，输出并停止。
t = func3()
print(t)

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python中try except处理程序异常的三种常用方法

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方法一：捕获所有异常

try:    a=b
     b=c
     except Exception as e:
         print(e)
      finally:##finally语句块是无论如何都要执行
          print("whatever will do")

name ‘c’ is not defined whatever will do

try:
    b=1
except Exception as e:
    print(e)
finally:# finally语句块是无论如何都要执行
print("whatever will do")

whatever will do

方法二：采用traceback模块查看异

#引入python中的traceback模块，跟踪错误import traceback 
try:
    a=b     
    b=c
except:    
   traceback.print_exc()

Traceback (most recent call last): File “”, line 5, in b=c NameError: name ‘c’ is not defined

方法三：采用sys模块回溯最后的异常

#引入sys模块
import sys
try:
    a=b    
    b=c
except:
    info=sys.exc_info()
    print (info[0],":",info[1])

: name ‘b’ is not defined