What is the correct way to break a long expression across multiple lines?

Question

This is probably a very simple question and I am probably not using the right keywords in my search; but I have a long expression that I would like to break across multiple lines to improve readability.

I believe this can be done with a \ at the end of the line to be continued but want to be sure.

Answer 1

When Mathematica encounters an incomplete expression, it will just continue reading on the next line. For example,

1 +
2

is the same as 1+2.

However,

1
+ 2

is interpreted as two distinct inputs, 1 (which is complete) and +2.

---

As you mentioned, \ can also be used at the end of the line to indicate continuation. So

1 \
+ 2

is also equivalent to 1+2. However, this doesn't seem to work when used in a notebook cell in the front end. Apparently it only works when running Mathematica in command line mode.

Answer 2

For completeness, the issue of the interpreter prematurely thinking a line end completes an expression is avoided by the use of enclosing parentheses:

(
1
+ 2
)

3

This may be safer than taking care about where you break lines. (And maybe you like the way it looks with the operators out front)

This applies inside any other construct as well, eg this works as expected:

 Table[
     i
     + 2 
         , {i,2}]

{3,4}

Answer 3

You may type "esc" + "cont" + "esc" then you could type "Enter" key. https://reference.wolfram.com/language/ref/character/Continuation.html