Python怎么return后让循环继续运行?
执行到return语句时,会退出函数,return之后的语句不再执行。
但将return语句放在try语句块中,是个例外,finally语句块中的语句依然会执行 。
举例:
正常函数:执行到该return语句时,函数终止,后边的语句不再执行
def fun():
print 98
return 'ok'
print 98
try语句中:finally语句块中的语句依然会执行 。
def func():
try:
print 98
return 'ok'
finally:
print 98
扩展资料:
return 语句会终止函数的执行,并返回函数的值。
语法:
return value;
可选项 value指定返回的值。如果忽略则返回undefined。
在函数中 ,return 语句用于终止一个函数的执行,并返回值value。
如果value被省略或在函数内没有 return 语句被执行,则函数返回undefined。
return语句的用法 :
1、中止函数的执行,并返回函数执行的结果。
语法为:return+表达式
return 返回的值可以是任何数据类型 。
2、使用return阻止某些浏览器默认的行为。
语法为:return false;
return 会直接另函数返回,函数就运行结束了,所有该函数体内的代码都不再执行了,所以该函数体内的循环也不可能再继续运行。
如果你需要让循环继续执行,就不能return函数,而应该选用break或者continue。
break:跳出所在的当前整个循环,到外层代码继续执行。
continue:跳出本次循环,从下一个迭代继续运行循环,内层循环执行完毕,外层代码继续运行。
return:直接返回函数,所有该函数体内的代码(包括循环体)都不会再执行。
用下边的示例代码来解释:
def return_continue_break(type):
if(not type in ["return", "continue", "break"]):
print '"type" should be "return, continue, break".'
return
for j in range(0, 10):
for i in range(0, 10):
print "j_i: %d_%d" %(j, i)
if(i > 3):
if(type == "return"):
return
elif(type == "continue"):
continue
else:
break
print "executed!"
if __name__ == '__main__':
return_continue_break("break")
return_continue_break("continue")
return_continue_break("return")
BREAK的输出为:
j_i: 0_0
executed!
j_i: 0_1
executed!
j_i: 0_2
executed!
j_i: 0_3
executed!
j_i: 0_4
j_i: 1_0
executed!
j_i: 1_1
executed!
j_i: 1_2
executed!
j_i: 1_3
executed!
j_i: 1_4
j_i: 2_0
executed!
j_i: 2_1
executed!
j_i: 2_2
executed!
j_i: 2_3
executed!
j_i: 2_4
j_i: 3_0
executed!
j_i: 3_1
executed!
j_i: 3_2
executed!
j_i: 3_3
executed!
j_i: 3_4
j_i: 4_0
executed!
j_i: 4_1
executed!
j_i: 4_2
executed!
j_i: 4_3
executed!
j_i: 4_4
j_i: 5_0
executed!
j_i: 5_1
executed!
j_i: 5_2
executed!
j_i: 5_3
executed!
j_i: 5_4
j_i: 6_0
executed!
j_i: 6_1
executed!
j_i: 6_2
executed!
j_i: 6_3
executed!
j_i: 6_4
j_i: 7_0
executed!
j_i: 7_1
executed!
j_i: 7_2
executed!
j_i: 7_3
executed!
j_i: 7_4
j_i: 8_0
executed!
j_i: 8_1
executed!
j_i: 8_2
executed!
j_i: 8_3
executed!
j_i: 8_4
j_i: 9_0
executed!
j_i: 9_1
executed!
j_i: 9_2
executed!
j_i: 9_3
executed!
j_i: 9_4
RETURN的输出为:
j_i: 0_0
executed!
j_i: 0_1
executed!
j_i: 0_2
executed!
j_i: 0_3
executed!
j_i: 0_4
CONTINUE的输出为:
j_i: 0_0
executed!
j_i: 0_1
executed!
j_i: 0_2
executed!
j_i: 0_3
executed!
j_i: 0_4
j_i: 0_5
j_i: 0_6
j_i: 0_7
j_i: 0_8
j_i: 0_9
j_i: 1_0
executed!
j_i: 1_1
executed!
j_i: 1_2
executed!
j_i: 1_3
executed!
j_i: 1_4
j_i: 1_5
j_i: 1_6
j_i: 1_7
j_i: 1_8
j_i: 1_9
j_i: 2_0
executed!
j_i: 2_1
executed!
j_i: 2_2
executed!
j_i: 2_3
executed!
j_i: 2_4
j_i: 2_5
j_i: 2_6
j_i: 2_7
j_i: 2_8
j_i: 2_9
j_i: 3_0
executed!
j_i: 3_1
executed!
j_i: 3_2
executed!
j_i: 3_3
executed!
j_i: 3_4
j_i: 3_5
j_i: 3_6
j_i: 3_7
j_i: 3_8
j_i: 3_9
j_i: 4_0
executed!
j_i: 4_1
executed!
j_i: 4_2
executed!
j_i: 4_3
executed!
j_i: 4_4
j_i: 4_5
j_i: 4_6
j_i: 4_7
j_i: 4_8
j_i: 4_9
j_i: 5_0
executed!
j_i: 5_1
executed!
j_i: 5_2
executed!
j_i: 5_3
executed!
j_i: 5_4
j_i: 5_5
j_i: 5_6
j_i: 5_7
j_i: 5_8
j_i: 5_9
j_i: 6_0
executed!
j_i: 6_1
executed!
j_i: 6_2
executed!
j_i: 6_3
executed!
j_i: 6_4
j_i: 6_5
j_i: 6_6
j_i: 6_7
j_i: 6_8
j_i: 6_9
j_i: 7_0
executed!
j_i: 7_1
executed!
j_i: 7_2
executed!
j_i: 7_3
executed!
j_i: 7_4
j_i: 7_5
j_i: 7_6
j_i: 7_7
j_i: 7_8
j_i: 7_9
j_i: 8_0
executed!
j_i: 8_1
executed!
j_i: 8_2
executed!
j_i: 8_3
executed!
j_i: 8_4
j_i: 8_5
j_i: 8_6
j_i: 8_7
j_i: 8_8
j_i: 8_9
j_i: 9_0
executed!
j_i: 9_1
executed!
j_i: 9_2
executed!
j_i: 9_3
executed!
j_i: 9_4
j_i: 9_5
j_i: 9_6
j_i: 9_7
j_i: 9_8
j_i: 9_9
希望对你有帮助。
如果你需要让循环继续执行,就不能return函数,而应该选用break或者continue。
break:跳出所在的当前整个循环,到外层代码继续执行。
continue:跳出本次循环,从下一个迭代继续运行循环,内层循环执行完毕,外层代码继续运行。
return:直接返回函数,所有该函数体内的代码(包括循环体)都不会再执行。
用下边的示例代码来解释:
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def return_continue_break(type):
if(not type in ["return", "continue", "break"]):
print '"type" should be "return, continue, break".'
return
for j in range(0, 10):
for i in range(0, 10):
print "j_i: %d_%d" %(j, i)
if(i > 3):
if(type == "return"):
return
elif(type == "continue"):
continue
else:
break
print "executed!"
if __name__ == '__main__':
return_continue_break("break")
return_continue_break("continue")
return_continue_break("return")
BREAK的输出为:
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j_i: 0_0
executed!
j_i: 0_1
executed!
j_i: 0_2
executed!
j_i: 0_3
executed!
j_i: 0_4
j_i: 1_0
executed!
j_i: 1_1
executed!
j_i: 1_2
executed!
j_i: 1_3
executed!
j_i: 1_4
j_i: 2_0
executed!
j_i: 2_1
executed!
j_i: 2_2
executed!
j_i: 2_3
executed!
j_i: 2_4
j_i: 3_0
executed!
j_i: 3_1
executed!
j_i: 3_2
executed!
j_i: 3_3
executed!
j_i: 3_4
j_i: 4_0
executed!
j_i: 4_1
executed!
j_i: 4_2
executed!
j_i: 4_3
executed!
j_i: 4_4
j_i: 5_0
executed!
j_i: 5_1
executed!
j_i: 5_2
executed!
j_i: 5_3
executed!
j_i: 5_4
j_i: 6_0
executed!
j_i: 6_1
executed!
j_i: 6_2
executed!
j_i: 6_3
executed!
j_i: 6_4
j_i: 7_0
executed!
j_i: 7_1
executed!
j_i: 7_2
executed!
j_i: 7_3
executed!
j_i: 7_4
j_i: 8_0
executed!
j_i: 8_1
executed!
j_i: 8_2
executed!
j_i: 8_3
executed!
j_i: 8_4
j_i: 9_0
executed!
j_i: 9_1
executed!
j_i: 9_2
executed!
j_i: 9_3
executed!
j_i: 9_4
RETURN的输出为:
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j_i: 0_0
executed!
j_i: 0_1
executed!
j_i: 0_2
executed!
j_i: 0_3
executed!
j_i: 0_4
CONTINUE的输出为:
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j_i: 0_0
executed!
j_i: 0_1
executed!
j_i: 0_2
executed!
j_i: 0_3
executed!
j_i: 0_4
j_i: 0_5
j_i: 0_6
j_i: 0_7
j_i: 0_8
j_i: 0_9
j_i: 1_0
executed!
j_i: 1_1
executed!
j_i: 1_2
executed!
j_i: 1_3
executed!
j_i: 1_4
j_i: 1_5
j_i: 1_6
j_i: 1_7
j_i: 1_8
j_i: 1_9
j_i: 2_0
executed!
j_i: 2_1
executed!
j_i: 2_2
executed!
j_i: 2_3
executed!
j_i: 2_4
j_i: 2_5
j_i: 2_6
j_i: 2_7
j_i: 2_8
j_i: 2_9
j_i: 3_0
executed!
j_i: 3_1
executed!
j_i: 3_2
executed!
j_i: 3_3
executed!
j_i: 3_4
j_i: 3_5
j_i: 3_6
j_i: 3_7
j_i: 3_8
j_i: 3_9
j_i: 4_0
executed!
j_i: 4_1
executed!
j_i: 4_2
executed!
j_i: 4_3
executed!
j_i: 4_4
j_i: 4_5
j_i: 4_6
j_i: 4_7
j_i: 4_8
j_i: 4_9
j_i: 5_0
executed!
j_i: 5_1
executed!
j_i: 5_2
executed!
j_i: 5_3
executed!
j_i: 5_4
j_i: 5_5
j_i: 5_6
j_i: 5_7
j_i: 5_8
j_i: 5_9
j_i: 6_0
executed!
j_i: 6_1
executed!
j_i: 6_2
executed!
j_i: 6_3
executed!
j_i: 6_4
j_i: 6_5
j_i: 6_6
j_i: 6_7
j_i: 6_8
j_i: 6_9
j_i: 7_0
executed!
j_i: 7_1
executed!
j_i: 7_2
executed!
j_i: 7_3
executed!
j_i: 7_4
j_i: 7_5
j_i: 7_6
j_i: 7_7
j_i: 7_8
j_i: 7_9
j_i: 8_0
executed!
j_i: 8_1
executed!
j_i: 8_2
executed!
j_i: 8_3
executed!
j_i: 8_4
j_i: 8_5
j_i: 8_6
j_i: 8_7
j_i: 8_8
j_i: 8_9
j_i: 9_0
executed!
j_i: 9_1
executed!
j_i: 9_2
executed!
j_i: 9_3
executed!
j_i: 9_4
j_i: 9_5
j_i: 9_6
j_i: 9_7
j_i: 9_8
j_i: 9_9
你说的是continue吧,在循环内结束,然后进行下一次循环,下面是我写的例子,你看一下。
for i in range(10):
#如果是2的倍数,那么不执行接下来的动作,你改成break试一下,会有别的情况
if i % 2 == 0:
continue
#打印
print i
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2014-02-09
import os
import glob
import shutil
backuptarget = r'E:\backup'
srcpath = r'D:\workspace\Projects\DNCSS\python'
def target_mapper(fullpath):
''' 根据文件名映射目标文件名
path, fname = os.path.split(fullpath)
return os.path.join(backuptarget, fname)
for f in glob.glob(os.path.join(srcpath,'log', '*.log')):
try:
shutil.move(f, target_mapper(f))
except:
continue # 再循环中捕获到异常后要求继续即可
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