Question

Why does 4 < '3' return True in Python 2?

Is it because when I place single quotes around a number Python sees it as a string and strings are bigger than numbers?

Answer 1

Yes, any number will be less than any string (including the empty string) in Python 2.

In Python 3, you can’t make arbitrary comparisons. You’ll get a TypeError.

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From the link in eryksun’s comment:

if (PyNumber_Check(v))
    vname = "";
else
    vname = v->ob_type->tp_name;
if (PyNumber_Check(w))
    wname = "";
else
    wname = w->ob_type->tp_name;
c = strcmp(vname, wname);

So at least in recent versions of CPython 2.x, type names are compared, with an empty string used instead of the type name for any numeric type.