W06: 3/21
===

以上週作業為例，解析迴圈運作。

### Ex1:

a = [3,2,7,4,6]
y = 0
for x in a:
  y = y+x
print(y)

| | 1 | 2 | 3 | 4 | 5 | final |
| --- | --- | --- | --- | --- | --- | ----- |
| x | 3 | 2 | 7 | 4 | 6 | |
| y | 3 | 5 | 12 | 16 | 22 | 22 |

`a=[3,2,7,4,6]`

### Ex2:

a=[3,2,7,4,6]
y=0
z=0
a.append(9)
for x in a:
  z+=x #x累加
  print(f"x: {x}") #過程
  print(f"y: {y}")
  print(f"z: {z}")
  print(f"a: {a}")
  print("------")
   
print("final result:") #結果
print(f"x: {x}")
print(f"y: {y}")
print(f"z: {z}")
print(f"a: {a}")

| | 1 | 2 | 3 | 4 | 5 | 6 | final |
| --- | --- | --- | --- | --- | --- | --- | ----- |
| x | 3 | 2 | 7 | 4 | 6 | 9 | |
| y | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| z | 3 | 5 | 12 | 16 | 22 | 31 | 31 |

`a=[3,2,7,4,6,9]`