Are てからでないと and てからで なければ the same?

I learned them in N3 shinkanzen book and I was confused. Are they the same?
Can I use them interchangeably?
CC BY-SA 4.0
2021-11-15T13:11:39.180
91211
2021-11-16T00:52:17.320
2021-11-15T16:45:38.043
30454
48735
question
grammar word-choice usage
Are てからでないと and てからで なければ the same?
They are mostly interchangeable, but there are differences.

  * ないと sounds relatively informal and should be avoided in very formal situations. On the other hand, なければ sounds formal and should be avoided in very casual conversations. Whichever is fine in day-to-day business conversations, although なければ sounds politer.

  * ないと is normally followed by another negation and form a double-negative sentence that effectively means "must". なければ does not have this restriction.

なければ | ないと | meaning  
---|---|---  
食べなければいけない。  
食べなければダメだ。 | 食べないといけない。  
食べないとダメだ。 | I must eat it.  
食べなければ。 | 食べないと。 | I must eat it.  
(another negation is implied)  
食べなければ良い。 | ❌ ~~食べないと良い。~~ | I will be fine if I avoid eating it.  
食べてからでなければいけない。  
食べてからでなければダメだ。 | 食べてからでないといけない。  
食べてからでないとダメだ。 | I must eat it first.  
食べてからでなければ。 | 食べてからでないと。 | I must eat it first.  
(another negation is implied)  
食べてからでなければ良い。 | ❌ ~~食べてからでないと良い。~~ | I'm fine if it doesn't happen after
eating.
CC BY-SA 4.0
2021-11-16T00:34:35.280
91216
2021-11-16T00:52:17.320
2021-11-16T00:52:17.320
5010
5010
91211
answer