Who created Julia?

Julia was originally released in 2012 by Alan Edelman, Stefan Karpinski, Jeff Bezanson, and Viral Shah.

Why Julia was created?

Julia addresses the “two-language problem” by providing a high-level and fast language that allows researchers to use a single language for both prototyping and production-level code, eliminating the need for a separate, lower-level language for computationally intensive tasks. Easy as Python and fast as C.

Why the name?

That’s everybody’s favorite question. There’s no good reason, really. It just seemed like a pretty name. - Stefan Karpinski

fun fact: The julia extension actually used to be .j. and they changed it into .jl

Printing in Julia

  1. Using the print() function to print a string or any other data type to the console.
julia> print("without new line")
without new line
julia>
  1. Using the println() function to print a string or any other data type to the console and append a newline character (\n) at the end.
julia> println("with new line")
with new line

julia>
  1. Using the printf() function to print formatted output to the console, similar to C’s printf function.
julia> using Printf
julia> @printf "to format the printed string, like this:  %i, %s" 100 "👍"
to format the printed string, like this:  100, 👍
julia>

also @sprintf("%Fmt", args...) Return @printf formatted output as string.

julia> @sprintf "this is a %s %15.1f" "test" 34.567
"this is a test            34.6"

  • The 15 specifies the total width of the printed field, including padding or signs, ensuring a minimum of 15 characters in the resulting string, including decimal point and leading spaces or signs.

  • The .1 specifies the floating-point number’s precision for digits to the right of the decimal point. Here, it’s 1, resulting in one digit to the right of the decimal point.

  1. Using the @show macro to print both the expression and its result, similar to Python’s print() function with the repr option enabled.
julia> @show("@show macro Shows expression and result, returns final result value.")
"@show macro Shows expression and result, returns final result value." = "@show macro Shows expression and result, returns final result value."
"@show macro Shows expression and result, returns final result value."

julia>

Variables 

x = 10

julia> typeof(x)
Int64

Variable names must begin with a letter (A-Z or a-z), underscore, or a subset of Unicode code points greater than 00A0 also emojis are acceptable variable name.

Arithmetic Operations 

# Division
julia> 10 / 15
0.6666666666666666

# Fractions
julia> 10 // 15
2//3

# integer division, truncated to an integer
julia> 10 ÷ 15
0

julia> 15 ÷ 10
1

# Inverse division
julia> 10 \ 3
0.3

# Modulus/Remainder
julia> 11 % 4
3

Bitwise Operations

Bitwise NOT (~):

To calculate bitwise NOT(negation), think of ~i=-i-1

julia> x = 11
11

julia> ~x
-12
Bitwise AND Operator (&): 
# Bitwise AND
julia> 5 & 3
1
Bitwise Inclusive OR (|): 
julia> 10 | 12
14

  1010
  1100
-------
  1110

10 = 1010 and 12 = 1110 in binary. 1010 | 1100 = 1110 in binary, which is 14 in decimal.

Bitwise Exclusive OR (⊻): 
julia> 10 ⊻ 12
6

To show ⊻ symbol, in REPL do \xor and press the tab it’ll convert into ⊻ symbol.

  1010
  1100
-------
  0110

10 = 1010 and 12 = 1110 in binary. 1010 ⊻ 1100 = 0110 in binary, which is 6 in decimal.

Logical Shift Right (>>>):

214 = 11010110 in binary, if we perform a logical shift right by 2 positions, then it’ll be 00110101 = 53 in decimal, the bits have been shifted two positions to the right, and zeros have been inserted from the left.

julia> 214 >>> 2
53
Arithmetic Shift Right (>>): 
julia> -42 >> 2
-11

value = -42  # Binary: 11111111_11111111_11111111_11010110 (assuming 32-bit two's complement representation)
shifted_value = value >> 2  # Arithmetic shift right by 2 positions
println(shifted_value)  # Output: -11 (Binary: 11111111_11111111_11111111_11110101)
Arithmetic Shift Left (<<): 
julia> -42 << 2
-168

value = -42  # Binary: 11111111_11111111_11111111_11010110 (assuming 32-bit two's complement representation)
shifted_value = value << 2  # Arithmetic shift left by 2 positions
println(shifted_value)  # Output: -168 (Binary: 11111111_11111111_11111111_10110000)

For Loop 

julia> arr = [1, 2, 3, 4]
5-element Vector{Int64}:
 1
 2
 3
 4

julia> for i in arr
          println(i)
       end
1
2
3
4

julia> for n in 1:3
           println(n)
       end
1
2
3

While Loop 

julia> n = 0
0

julia> while n < 3
           n += 1
           println(n)
       end
1
2
3

Comments 

# This is a single line comment

#=
This is a multiline comment
=#

String Interpolation 

julia> a = 3
7

julia> b = 5
5

julia> str = "a is $a. b is $b. a*b is $(a*b)";

julia> println(str)
a is 3. b is 5. a*b is 15