python什么时候选择实习字符串 [英] When does python choose to intern a string

问题描述

<预><代码>>>>s1 = "垃圾邮件">>>s2 = "垃圾邮件">>>s1 是 s2真的>>>q = 'asdalksdjfla;ksdjf;laksdjfals;kdfjasl;fjasdf'>>>r = 'asdalksdjfla;ksdjf;laksdjfals;kdfjasl;fjasdf'>>>q 是 r错误的

s1 is s2 给 False 应该有多少个字符?极限在哪里?即，我在问一个字符串在 python 开始制作它的单独副本之前必须有多长.

解决方案

字符串实习是特定于实现的，不应依赖，如果您想检查两个字符串是否相同，请使用相等测试.

>>> s1 = "spam"
>>> s2 = "spam"
>>> s1 is s2
True
>>> q = 'asdalksdjfla;ksdjf;laksdjfals;kdfjasl;fjasdf'
>>> r = 'asdalksdjfla;ksdjf;laksdjfals;kdfjasl;fjasdf'
>>> q is r
False

How many characters should have to s1 is s2 give False? Where is limit? I.e., I am asking how long a string has to be before python starts making separate copies of it.

解决方案

String interning is implementation specific and shouldn't be relied upon, use equality testing if you want to check two strings are identical.

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