str1 = "This is a ‘test‘"
print(str1)

str1 = ‘This is a "test"‘
print(str1)

str1 = "This is a \"test\""
print(str1)

str1 = ‘This is a \‘test\‘ ‘
print(str1)

str1 = "This is a single string"
print(str1)

‘‘‘
len()
lower()
upper()
str()
‘‘‘

print(len("abc"))
print("aAbc".lower())
print("abc".upper())
print("abc" 
 
+  str(2))
print("hello" + " " + "world")

result:

C:\Users\FeiLiu\AppData\Local\Programs\Python\Python36\python.exe C:/Users/FeiLiu/PycharmProjects/GetBluePageInfo/src/stringTest.py
This is a ‘test‘
This is a "test"
This is a "test"
This is a ‘test‘ 
This is a single string
3
aabc
ABC
abc2
hello world

python學習（二十二） String