python函數中的return

Ⅰ python怎麼return後讓循環繼續運行

return 會直接另函數返回，函數就運行結束了，所有該函數體內的代碼都不再執行了，所以該函數體內的循環也不可能再繼續運行。

如果你需要讓循環繼續執行，就不能return函數，而應該選用break或者continue。
break：跳出所在的當前整個循環，到外層代碼繼續執行。
continue：跳出本次循環，從下一個迭代繼續運行循環，內層循環執行完畢，外層代碼繼續運行。
return：直接返回函數，所有該函數體內的代碼（包括循環體）都不會再執行。

用下邊的示例代碼來解釋：

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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的輸出為：

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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的輸出為：

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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的輸出為：

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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

Ⅱ python中return函數的用法

在 Python 中，「return」函數的用法如下：

1、return 語句用於退出函數，終止函數並將 return 值傳回。實例：

>>>defa(x,y):
>>>ifx==y:
>>>returnx,y

2、用於同一循環語句下，遇到第一個 return 後即返回。實例：

```python
>>>deffun(a,b):
print(a)
returna
print(b)
returnb

>>>resunlt=fun(2,6)
2
```

3、用於 return 在不帶參數的情況下（或者沒有寫 return 語句），默認返回 None。實例：

defrecurve(a,b):
ifa%b==0:
returnb
else:
gcd(b,a%b)

以上內容參考：網路-Python