1.修改字符串首字母的大小寫
代碼演示:
s1 = 'hello'
print(s1)
print(s1.capitalize())
#s1[0] = 'H' 只讀的,會拋出異常
s1 = s1[0:1] + s1[1].upper() + s1[2:]
print(s1)
s2 = 'Hello'
s = s2[0].lower() + s2[1:]
print(s)
運行結果:
2.如何將字符串中每一個單詞的首字母變成大寫
代碼演示:
s3 = 'hello world'
print(s3.capitalize())
a = s3.split(' ')
new_str = f'{a[0].capitalize()} {a[1].capitalize()}'
print(new_str)
運行結果:
3.如何反轉一個字符串
代碼演示:
s1 = 'abcd'
s2 = ""
for i in s1: #麻煩
s2 = i + s2
print(s2)
運行結果:
4.如何用切片反轉字符串
代碼演示:
s1 = 'abcd'
print(s1[::1]) #簡便
print(s1[::2])
print(s1[::-1])
運行結果:
用到的知識點:
1. capitalize 只有字符串的首字母大寫
2. upper 將字符串當中所有的字母轉換爲大寫
3. lower 將字符串當中所有的字母轉換爲小寫