使用String literals宣告

單行

單引號(')或雙引號(")都可以，官方文件提到差別只有用其中一個時不需對另一個標示為逃脫字元

The only difference between the two is that within single quotes you don’t need to escape " (but you have to escape ') and vice versa.

可以使用反斜號(\)逃脫某些字元。官方逃脫字元列表在這裡

多行

使用三個單引號(''')或是三個雙引號(""")。可以使用反斜號(\)達到不換行的效果。

其他

針對單行宣告，PEP8並無特別推薦使用單引號或雙引號。對於多行，PEP8建議使用三個雙引號(""")

This PEP does not make a recommendation for this.
For triple-quoted strings, always use double quote characters to be consistent with the docstring convention in PEP 257.
https://www.python.org/dev/peps/pep-0008/#string-quotes

s1 = "single line's \"declaration\""
s2 = 'another single line\'s "declaration"'
print(s1)
print(s2)

m1 = """\
first line
second line \
,follow by second line
"""
print(m1)

特性

immutable。宣告後就沒辦法修改。

# immutable
wrong_str = "irenman"
print(wrong_str)
print("id of wrong_str: {}".format( id(wrong_str) ))
print("error char is index 2 \"{}\"".format(wrong_str[2]))

wrong_str_2 = "irenman"
print(wrong_str_2)
print("id of wrong_str_2: {}".format( id(wrong_str_2) ))

# edit
wrong_str[2] = "o"

參考

• python 官方
  • tutorial - 3.1.2. Strings
  • library - 4.7. Text Sequence Type - str
• Google's Python Class - strings
• An Introduction to Working with Strings in Python 3