{"id":81,"date":"2011-05-19T08:25:00","date_gmt":"2011-05-19T08:25:00","guid":{"rendered":"https:\/\/www.root42.de\/blog\/?p=81"},"modified":"2011-05-19T08:25:00","modified_gmt":"2011-05-19T08:25:00","slug":"is-not-none-maybe-something","status":"publish","type":"post","link":"https:\/\/www.root42.de\/blog\/?p=81","title":{"rendered":"Is “not None” maybe “Something”?"},"content":{"rendered":"

I just had a funny thought. In Python you can write:<\/p>\n

if not someObject is None:
    someObject.doSomething()
else:
    print \"someObject is None!\"
<\/pre>\n
This reads a bit strange. So what if you could alias “not … is None” to “… is Something”?<\/p>\n
if someObject is Something:
    someObject.doSomething()
else:
    print \"someObject is None!\"
<\/pre>\n
<\/p>\n
It seems that this idea was thought of<\/a> almost eight years ago already. This lead to some PEP 0326, which got rejected. If Python were a macro or functional language, you could probably hack something up to do the same thing, but it does not work like that:<\/div>\n
<\/p>\n
>>> Something = not None
>>> Something
True
>>> A = [1,2,3]
>>> if A is Something:
...     print \"This is something\"
... else:
...     print \"This is nothing\"
... 
This is nothing
>>> 
<\/pre>\n
<\/p>\n
The problem here being, that “non None” is immediately evaluated to “True”, since “None” can be implicitly converted to “False” in a boolean sense. Was a funny thought, though.<\/div>\n
<\/p>\n
Update: Turns out you can at least write “if someObject is not None:”, which is more readable. <\/div>\n","protected":false},"excerpt":{"rendered":"
I just had a funny thought. In Python you can write: if not someObject is None: someObject.doSomething()else: print “someObject is None!” This reads a bit strange. So what if you could alias “not … is None” to “… is Something”? if someObject is Something: someObject.doSomething()else: print “someObject is None!” It seems that this idea was … Continue reading “Is “not None” maybe “Something”?”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[7,15],"tags":[],"_links":{"self":[{"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/posts\/81"}],"collection":[{"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=81"}],"version-history":[{"count":0,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/posts\/81\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=81"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=81"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=81"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}