04-python第四天學習

（1）for迴圈里的else

In [1]: nums = [11,22,33,44]

In [2]: for temp in nums:
   ...:     print(temp)
   ...: else:　　　　#else表示當迴圈列印完才會列印else里的內容
   ...:     print("========")
   ...:     
11
22
33
44
========

（2）列表append的註意點

In [3]: a = [11,22,33]

In [4]: b = [44,55]

In [5]: a.append(b)

In [6]: a
Out[6]: [11, 22, 33, [44, 55]]　　#append相當於把b列表這個整體都放在a列表

In [1]: a = [11,22,33]

In [2]: b = [44,55]

In [3]: a.append(b)

In [4]: a
Out[4]: [11, 22, 33, [44, 55]]

In [5]: a = a.append(b)　　#當執行a.append(b)時，代表已經把b添加到a裡面去了，結果已經發生了變化，但是a.append(b)並沒有結果輸入，則會返回空

In [6]: a