python, using is to compare two strings, why does the following result appear:
In [1]: x = "ab"
y = "ab"
x is y
Out[1]: True
In [2]: x = "a123b"
y = "a123b"
x is y
Out[2]: True
In [3]: x = "a,b"
y = "a,b"
x is y
Out[3]: False
In [4]: x = "-sharp1"
y = "-sharp1"
x is y
Out[4]: False is compares whether the id of two objects is the same.
when the two are integers: if the value is between [- 5256], the two variables use objects in the same object pool, so the address is the same; if the value exceeds this range, a new piece of memory has to be opened up when the value is defined, and the address is different;
when the two are strings: if the value contains only numbers and letters, the two are the same.
when the two are dictionaries, tuples, and lists, the two are inconsistent.
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