下表列出了所有Python语言支持的标识运算符。
| 运算符 | 描述 | 示例 |
|---|---|---|
| is | 计算结果为true，如果操作符两侧的变量指向相同的对象，否则为false。 | x是y，这里结果是1，如果id(x)的值为id(y)。 |
| is not | 计算结果为false，如果两侧的变量操作符指向相同的对象，否则为true。 | x不为y，这里结果不是1，当id(x)不等于id(y)。 |
示例：
试试下面的例子就明白了所有Python编程语言提供的标识运算符：
#!/usr/bin/pythona = 20b = 20if ( a is b ): print "Line 1 - a and b have same identity"else: print "Line 1 - a and b do not have same identity"if ( id(a) == id(b) ): print "Line 2 - a and b have same identity"else: print "Line 2 - a and b do not have same identity"b = 30if ( a is b ): print "Line 3 - a and b have same identity"else: print "Line 3 - a and b do not have same identity"if ( a is not b ): print "Line 4 - a and b do not have same identity"else: print "Line 4 - a and b have same identity"
当执行上面的程序它会产生以下结果：
Line 1 - a and b have same identity Line 2 - a and b have same identity Line 3 - a and b do not have same identity Line 4 - a and b do not have same identity
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