1.index out of range!!!!!
strs = ["flower","flow","flight"]
res = len(strs[index]) ## 要保證strs的index位置不爲空才能使用!!!!
## 如,len(strs[0]) 時, 要是strs = [], 會報錯index out of range!!!!
2.TypeError: 'str' object does not support item assignment
str1 = "Tomorrow is another day"
str1[10] = 'I' ##報錯!!!因爲string(區別於list)是一種不可變的數據類型
str1 = str1[:10] + 'I' + str1[10:] ##應該用這種拼接的方式代替