Variables

A variable is a name that will be associated to a value through a memory space; these are case-sensitive.

Defining variables

Variables are defined and modified using =, see some examples below.

x = 10
print(x, " is a ", typeof(x))

10 is a Int64

x = 10.0
print(x, " is a ",  typeof(x))

10.0 is a Float64

x = "Hello World!"
print(x, " is a ",  typeof(x))

Hello World! is a String

x = 1 + 2im
print(x, " is a ",  typeof(x))

1 + 2im is a Complex{Int64}

x = 1 // 2
print(x, " is a ",  typeof(x))

1//2 is a Rational{Int64}

More that one variable can be defined using tuples syntax.

(a, b) = (1, 10)
print(a, ", ", b)

1, 10

a, b = 1, 10
print(a, ", ", b)

1, 10

(a, b) = 1, 10
print(a, ", ", b)

1, 10

a, b = (1, 10)
print(a, ", ", b)

1, 10

Unicode names can be used. This helps to write code closer to mathematical equations.

μ = 0
print(μ)

σ² = 3
print(σ²)

α = 0.1
print(α)

0.1

β₀ = 10.0
print(β₀)

10.0

pi; pi = 3
# ERROR: cannot assign a value to variable MathConstants.pi from module Main
# Stacktrace:
#  [1] top-level scope at REPL[95]:1

sqrt(4); sqrt = 4
# ERROR: cannot assign a value to variable Base.sqrt from module Main
# Stacktrace:
#  [1] top-level scope at REPL[97]:1

else = false
# ERROR: syntax: unexpected "else"
# Stacktrace:
#  [1] top-level scope at none:1

myvariable::Int8 = 10

myvariable = 3.3
# ERROR: InexactError: Int8(3.3)

myvariable = "text"
ERROR: MethodError: Cannot `convert` an object of type String to an object of type Int8