A simple example of an Python string case conversion

All letters are converted to uppercase

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

if __name__ == "__main__":
a = 'hello, world!'
print (a upper ()) output:

HELLO, WORLD!

All the letters are converted to lowercase

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

if __name__ == "__main__":
a = 'HELLO, WORLD!'
print (a lower ()) output:

hello, world!

(3) convert the first letter to uppercase and the rest to lowercase

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

if __name__ == "__main__":
a = 'HELLO, WORLD!'
print (a capitalize ()) output:

Hello, world!

The first letter of all the words is converted to uppercase and the rest to lowercase

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

if __name__ == "__main__":
a = 'HELLO, WORLD!'
print (a title ()) output:

Hello, World!

All the letters are capitalized

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

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

b = 'hello, world!'
print (b isupper ()) output:

True
False

Judge that all letters are lowercase

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

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

b = 'hello, world!'
print (b islower ()) output:

False
True

Judge that the first letter of all the words is uppercase

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

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

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

c = 'Hello, World!'
print (c istitle ()) output:

False
False
True