Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
441 views
in Technique[技术] by (71.8m points)

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

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?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

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.


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.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...