可以使用==运算符或者__eq __()函数检查Python字符串是否相等。
Python字符串区分大小写，因此这些相等性检查方法也区分大小写。

Python字符串是否相等

让我们看一些示例，检查两个字符串是否相等。

s1 = 'Apple'

s2 = 'Apple'

s3 = 'apple'

# case sensitive equals check
if s1 == s2:
  print('s1 and s2 are equal.')

if s1.__eq__(s2):
  print('s1 and s2 are equal.')

输出：

s1 and s2 are equal.
s1 and s2 are equal.

如果要执行不相等检查，可以使用！=运算符。

if s1 != s3:
  print('s1 and s3 are not equal')

输出：s1和s3不相等

Python字符串等于不区分大小写的检查

有时我们在检查两个字符串是否相等时不在乎大小写，可以使用casecase()，lower()或者upper()函数进行不区分大小写的相等性检查。

if s1.casefold() == s3.casefold():
  print(s1.casefold())
  print(s3.casefold())
  print('s1 and s3 are equal in case-insensitive comparison')

if s1.lower() == s3.lower():
  print(s1.lower())
  print(s3.lower())
  print('s1 and s3 are equal in case-insensitive comparison')

if s1.upper() == s3.upper():
  print(s1.upper())
  print(s3.upper())
  print('s1 and s3 are equal in case-insensitive comparison')

输出：

apple
apple
s1 and s3 are equal in case-insensitive comparison
apple
apple
s1 and s3 are equal in case-insensitive comparison
APPLE
APPLE
s1 and s3 are equal in case-insensitive comparison

Python字符串等于特殊字符

让我们看一些字符串包含特殊字符的示例。

s1 = '$#ç∂'
s2 = '$#ç∂'

print('s1 == s2?', s1 == s2)
print('s1 != s2?', s1 != s2)
print('s1.lower() == s2.lower()?', s1.lower() == s2.lower())
print('s1.upper() == s2.upper()?', s1.upper() == s2.upper())
print('s1.casefold() == s2.casefold()?', s1.casefold() == s2.casefold())

输出：

s1 == s2? True
s1 != s2? False
s1.lower() == s2.lower()? True
s1.upper() == s2.upper()? True
s1.casefold() == s2.casefold()? True