pythonstring-interning

What determines which strings are interned and when?

>>> 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.

Solution

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