For 迴圈 會按順序從集合中取出每個項目，並將每次取出的項目，指定給你定義的變數
names = ['Christopher', 'Susan']
for name in names:
print(name)While 迴圈 只要進入迴圈的判斷條件為真 (True), 就會一直重複執行
names = ['Christopher', 'Susan']
index = 0
while index < len(names):
name = names[index]
print(name)
index = index + 1