Takeaway from restaurants and food stalls

Do most of restaurants in tokyo provide takeaway service?
Especially those 串烧bbq stalls in shinjuku such as 思い出横丁?

Thanks in advance!

Some restaurant do not sell food to-go, or do not allow packing leftover food to be taken home. If you want to buy food to-go, I recommend shopping in depa-chika (department store basement floor). Most department store locate food department in the basement floor, and that's where you can buy everything to-go. Most grocery stores have prepared food department, also. If you are visiting Shinjuku anyway (for 思い出横丁) you can ask to buy food to go. If they do not allow, then you can always go back to Shinjuku station and its chika (駅地下) where there are lots of stores that sell prepared food.

There are not many restaurants that can take out except at fast food restaurants.
Basically, in Japan, we do not have a custom of taking home the left food ordered at restaurant,
it means no using "doggy bag" custom. (restaurants that can be used is not zero, just minority)

This reason is not a responsibility after food poisoning occurred,
but because of customs from Japanese morals, it would be easy to understand if you know
the reasons the Japanese for saying "Itadaki masu" and "Gochiso sama".
http://nichigopress.jp/learn/jpculture/131185/

Recent years, the supply side often misjudges the prediction of demand and makes too much,
and their waste left food is a problem, but the custom of using doggy bag does not take root at all
and there is no indication of spreading, I also do not agree.

The first part answer is a problem in Japan as a whole,
but in Omoide Yokocho it is basically only eating in restaurants.
Some restaurants can also take out,
but "kushi yaki(串焼き)" you want to eat that fathed is the best than after take out no heated it.
If you only eat it in the hotel room, it would be more realistic to warm the frozen food
with a microwave, you can easily buy it not only at "depa-chika" but also "supermarkets".
(No recommend convenience stores one, bc they are not delicious just not enough variety.)

Omoide Yokocho is delightful for people who do not know are narrow spaces joined
and cheaply drinking with a sense of friends, so if you only want to eat delicious kushi yaki,
you should go to another restaurants, so until you come to Japan you will be enjoying talking
to foreign travelers other than Japanese if you do not feel stressed.

Thank you all for such informative explanations.
That's really kind of you not just answering the question but also elaborated further to introduce Japanese custom.