pythonidentitystring-comparisonobject-comparison

Python: Why does ("hello" is "hello") evaluate as True?

Why does "hello" is "hello" produce True in Python?

I read the following here:

If two string literals are equal, they have been put to same memory location. A string is an immutable entity. No harm can be done.

So there is one and only one place in memory for every Python string? Sounds pretty strange. What's going on here?

Solution

  • Python (like Java, C, C++, .NET) uses string pooling / interning. The interpreter realises that "hello" is the same as "hello", so it optimizes and uses the same location in memory.

    Another goodie: "hell" + "o" is "hello" ==> True