I don't understand when you use them and what the difference is between the three.
For example, when you say:
Japanese Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Japanese language. It only takes a minute to sign up.Sign up to join this community
Depending on the context, they can all mean:
because of/due to (a reason):
There were many people who lost their lives due to the earthquake.
by (a method/way/means):
Teachers check if students understand by (means of) tests.
by (identifies the agent of the action, particularly in a passive sentence):
Who was this machine invented by?
(just for comparison, here's that as an active sentence without
Who invented this machine?
dependant on (when highlighting differences):
Lifestyles differ depending on the country.
Because of a fire many forests burnt down.
An ox is taken by the horns and a man by word.
による is slightly different (i.e.
による is used in the following example because it's talking about a tsunami because of the earthquake):
There's no worry of a tsunami because of the earthquake this time.
I ended up reaching this post because I was looking for the answer while reading through the grammar but I think I finally understand.
Like user797 pointed out, によって is depending on/according to.
But whether or not you were asking this, I think want to know the difference from that compared to both による and によると. I'm assumign this because I was the most confused about this. The book I'm using specifically says that AによるとB means The information from 'B' depends on the actual source which is 'A'.
人によって意見は違う。 Opinions are different depending on the people. (no direct source) 彼によると悪い判断だった. According to him, it was a bad decision. (direct source is him)