Python -- 字符串大小写转换

①所有字母都转换为大写

# -*- coding:utf-8 -*-

if __name__ == "__main__":
a = 'hello, world!'
print(a.upper())输出：
HELLO, WORLD!

②所有字母都转换为小写
# -*- coding:utf-8 -*-

if __name__ == "__main__":
a = 'HELLO, WORLD!'
print(a.lower())输出：
hello, world!

③首字母转换成大写， 其余转换成小写
# -*- coding:utf-8 -*-

if __name__ == "__main__":
a = 'HELLO, WORLD!'
print(a.capitalize())输出：
Hello, world!

④所有单词的首字母转换成大写， 其余转换成小写
# -*- coding:utf-8 -*-

if __name__ == "__main__":
a = 'HELLO, WORLD!'
print(a.title())输出：
Hello, World!

⑤判断所有字母都为大写
# -*- coding:utf-8 -*-

if __name__ == "__main__":
a = 'HELLO, WORLD!'
print(a.isupper())

b = 'hello, world!'
print(b.isupper())输出：
True
False
⑥判断所有字母都为小写

# -*- coding:utf-8 -*-

if __name__ == "__main__":
a = 'HELLO, WORLD!'
print(a.islower())

b = 'hello, world!'
print(b.islower())输出：
False
True
⑦判断所有单词的首字母为大写
# -*- coding:utf-8 -*-

if __name__ == "__main__":
a = 'HELLO, WORLD!'
print(a.istitle())

b = 'hello, world!'
print(b.istitle())

c = 'Hello, World!'
print(c.istitle())输出：
False
False
True