How to reduce the number of return statements after if and elifs?

Question

I'm trying to develop a template that adapts itself after user input using Flask. I manage to make it work, but there are too many return statements.

if form == 'Y':
    return render_template("mypage.html",title = title_1, body = body_1)
elif form == 'N':
    return render_template("mypage.html",title = title_2, body = body_2)
else:
    return render_template("mypage.html",title = title_3, body = body_3)

Is there a way to reduce the return statements? I tried this, but it didn't work:

if form == 'Y':
   title_return = title_1, body = body_1
elif form == 'N':
   title_return = title_2, body = body_2
else:
   title_return = title_3, body = body_3

return render_template("mypage.html",title_return = title, body_return = body)

Lots of good answers below, but I guess I have to ask: what's the problem with having three return statements? — joanis, Dec 19 '21 at 18:32
"I tried this, but it didn't work:" Well, where you have the code `title_return = title_1, body = body_1`, what do you actually want that to do? You want to make two simultaneous assignments, right? So, [there's syntax for that](https://stackoverflow.com/questions/16409901/simultaneous-assignment-semantics-in-python). — Karl Knechtel, Dec 19 '21 at 18:33

yabadabaduhast · Accepted Answer · 2021-12-19T18:29:31.703

1

Your assignment in render_template is wrong. It will be fixed like below.

if form == 'Y':
   title_return, body_return = title_1, body_1
elif form == 'N':
   title_return, body_return = title_2 body_2
else:
   title_return, body_return = title_3, body_3

return render_template("mypage.html",title = title_return, body = body_return)

You can create a method to reduce code. That takes input and returns title and body.

edited Dec 19 '21 at 18:29

answered Dec 19 '21 at 18:26

yabadabaduhast

109
1
6

There isn't a `body_return`. It's just `body` – 12944qwerty Dec 19 '21 at 18:27
I edited the code. – yabadabaduhast Dec 19 '21 at 18:31
Thank you! It was more simple than I expected – interferemadly Dec 19 '21 at 19:46

score 1 · Answer 2 · answered Dec 19 '21 at 18:27

1

you reversed the parameter names and values in you last function call, and you never assigned body_return

If you change the commas to semi-colons in your if/elif/else statements, this should work:

if form == 'Y':
   title_return = title_1; body = body_1
elif form == 'N':
   title_return = title_2; body = body_2
else:
   title_return = title_3; body = body_3

return render_template("mypage.html",title=title_return, body=body)

answered Dec 19 '21 at 18:27

Alain T.

40,517
4
31
51

why use the semicolon, if you can use `title_return, body = title_1, body_1` and the same for others – Matiiss Dec 19 '21 at 18:31
That's true. I meant to minimize the number of changes. – Alain T. Dec 19 '21 at 18:31
Thanks! Your answer helped me too – interferemadly Dec 19 '21 at 19:47

veryverde · Answer 3 · 2021-12-19T18:33:44.940

1

You can create a dictionary that has two values, 'Y' and 'N'. Then you simply check if it's in and voilà:

temp_dictionary = {
   "Y": [title_1, body_1],
   "N": [title_2, body_2]
}

if form in temp_dictionary:
   title_return  = temp_dictionary[form][0]
   body  = temp_dictionary[form][1]
else:
   title_return  = title_3
   body  = body_3
return title_return, body

This way, you can also extend the dict later on, if necessary.

edited Dec 19 '21 at 18:33

answered Dec 19 '21 at 18:28

veryverde

444
3
13

you shouldn't use `dict` as a variable name and also you can unpack via `title_return, body = dct[form]` and `title_return, body = title_3, body_3`, or even shorter just do `title, body = dct.get(form, (title_3, body_3))` – Matiiss Dec 19 '21 at 18:32

How to reduce the number of return statements after if and elifs?

3 Answers3