One of my clients is writing software in Julia so I’m picking up the language. I looked at Julia briefly when it first came out but haven’t used it for work. My memory of the language was that it was almost a dialect of Python. Now that I’m looking at it a little closer, I can see more differences, though the most basic language syntax is more like Python than any other language I’m familiar with.
Here are a few scattered notes on Julia, especially on how it differs from Python.
- Array indices in Julia start from 1, like Fortran and R, and unlike any recent language that I know of.
- Like Python and many other scripting languages, Julia uses
#for one-line comments. It also adds
=#for multi-line comments, like
- By convention, names of functions that modify their first argument end in
!. This is not enforced.
- Blocks are indented as in Python, but there is no colon at the end of the first line, and there must be an
endstatement to close the block.
- Julia uses
elseifas in Perl, not
elifas in Python .
- Julia uses square brackets to declare a dictionary. Keys and values are separated with
=>, as in Perl, rather than with colons, as in Python.
- Julia, like Python 3, returns 2.5 when given
5/2. Julia has a
//division operator, but it returns a rational number rather than an integer.
- The number 3 + 4i would be written
3 + 4imin Julia and
3 + 4jin Python.
- Strings are contained in double quotes and characters in single quotes, as in C. Python does not distinguish between characters and strings, and uses single and double quotes interchangeably.
- Julia uses
- You can access the last element of an array with
end, not with -1 as in Perl and Python.
* * *
 Actually, Perl uses
elsif, as pointed out in the comments below. I can’t remember when to use