Python中的表达式和语句有什么区别？

本文翻译自：What is the difference between an expression and a statement in Python?

在Python中，表达式和语句之间有什么区别？

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#1楼

参考：https://stackoom.com/question/jPZf/Python中的表达式和语句有什么区别

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#2楼

A statement contains a keyword. 语句包含关键字。

An expression does not contain a keyword. 表达式不包含关键字。

print "hello" is statement, because print is a keyword. print "hello"是语句，因为print是关键字。

"hello" is an expression, but list compression is against this. "hello"是一个表达式，但是列表压缩与此相反。

The following is an expression statement, and it is true without list comprehension: 以下是一个表达式语句，没有列表理解也是如此：

(x*2 for x in range(10))

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#3楼

Statements represent an action or command eg print statements, assignment statements. 语句表示动作或命令，例如打印语句，赋值语句。

print 'hello', x = 1

Expression is a combination of variables, operations and values that yields a result value. 表达式是变量，运算和值的组合，产生结果值。

5 * 5 # yields 25

Lastly, expression statements 最后，表达式语句

print 5*5

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#4楼

I think an expression contains operators + operands and the object that holds the result of the operation... eg 我认为一个表达式包含运算符+操作数和持有该运算结果的对象...例如

var sum = a + b;

but a statement is simply a line of a code (it may be an expression) or block of code... eg 但是一条语句只是一行代码（可能是一个表达式）或代码块...例如

fun printHello(name: String?): Unit {
if (name != null)
    println("Hello ${name}")
else
    println("Hi there!")
// `return Unit` or `return` is optional

} }

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#5楼

Expressions: 表达式：

• Expressions are formed by combining objects and operators . 通过组合objects和operators来形成表达式。
• An expression has a value, which has a type. 表达式具有一个值，该值具有一个类型。
• Syntax for a simple expression: