Strings in Python have the data type str, spelled s‑t‑r, and we've been using them extensively already. Strings are sequences of Unicode code points, and for the most part, you can think of code points as being like characters, although they are not strictly equivalent. The sequence of characters in a Python string is immutable, meaning that once you've constructed a string, you can't modify its contents. Literal strings in Python are delimited by quotes, you could use single quotes or double quotes. You must, however, be consistent. For example, you can't use single quotes on one side and double on the other, like this. Supporting both quoting styles allows you to easily incorporate the other quote character into the literal string without resorting to ugly escape character. Notice that the REPL exploits the same quoting flexibility when echoing the strings back to us. Beautiful text strings rendered in literal form, simple elegance. At first sight, support for both quoting styles seems to violate an important principle of Pythonic style from the Zen of Python. There should be one, and preferably only one, obvious way to do it. In this case, however, another aphorism from the same source, practicality beats purity, takes precedence. The utility of supporting two quoting styles is valued more highly than the alternative, a single quoting style combined with more frequent use of ugly escape sequences, which we'll encounter shortly.

 

extensively	广泛地
equivalent	相等地
immutable	不可变的
delimit	界定
quote	引号
escape character	转义字符
literal	文字的，字面的
literal form	字面形式
take precedence	优先
rendered in literal form	以字面形式呈现
simple elegance	简单的优雅
at first sight	乍一看
violate an important principle	违反了重要的原则
preferably only one	只有一个更好/最好也只有一个
aphorism	格言
practicality beats purity	实用大于纯粹
we'll encounter shortly	我们很快就会遇到
alternative	二选一