Two questions about Julia

[Mason]

@hack3rcon

1- Why can’t I assign '' to a variable?

julia> ch = ''
ERROR: ParseError:
# Error @ REPL[17]:1:7
ch = ''
#     └ ── empty character literal
Stacktrace:
 [1] top-level scope
   @ none:1

This isn’t about assigning to a variable. The problem is that '' itself isn’t valid syntax. When you write 'a' that is syntax specifically for the single character a, not a string of characters. If you want to write an empty string you can do

julia> ch = ""
""

which creates an empty string. There is no definitive empty character, so '' is made to be a syntax error instead.

@hack3rcon

2- Why doesn’t Julia have a reverse for loop?

for h = 10 : 1

I know that this problem can be solved as follows:

for h = last : -1 : first

Thank you.

If you already know how to construct a reversed loop, then I’m not sure what to say. Yes, the second thing you wrote is the correct way to express a loop from last down to first.

The first thing you wrote is a loop over an empty range:

julia> length(10:1)
0

julia> length(10:-1:1)
10