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println("Greetings! স্বাগতম!")
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julia -v
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print(julia -v)
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pi
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typeof(1)
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WORD_SIZE
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typeof(ans)
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1/Inf
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1/0
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x = 3
(x-1)x
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x = 1
x+= 3
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z = hypot(1, 3)
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! + 2 im
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1 + 2im
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sqrt(4)
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sqrt(-1)
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2//3
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Int("x")
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Int('x')
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Char(120)
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'A' < 'a'
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str = "Hello, World"
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str[1]
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str[10]
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str[end]
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endof(str)
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mystring = "Hello World"
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mystring[6:6]
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mystring[6:7]
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this67 = mystring[6:7]
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typeof(this67)
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length(mystring)
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for i = 1:endof(mystring)
try
println(mystring[i])
catch
#ignore index error
end
end
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greet = "Hello"
whom = "World"
bothtogether = string(greet, ", ", whom)
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$greet $whom
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"$greet, $whom"
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v = [1,2,3]
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world = "world"
"Hello, $world"
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contains("Hello World", "world")
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contains("Hello World", "World")
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contains("Hello World", 'o')
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in("Hello World", 'o')
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# create repeats
myreps = repeat("x", 10)
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# you can join words and letters
thisJoined = join(["a", "b"],"," )
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myreg = r"^\x*(?:#|$)"
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typeof(ans)
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ismatch(myreg, "not a comment")
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match(myreg, "not a comment")
# will not result in anything
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match(myreg, "# a comment")
# will result in hash
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function myf(x,y)
z = x * y
end
myf(2,3)
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myf
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function g(x,y)
#return x * y
return x + y
end
g(2,3)
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+(1,2,3)
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function hypot(x,y)
x = abs(x)
y = abs(y)
if x > y
r = y/x
return x * sqrt(1+r*r)
end
if y == 0
return zero(x)
end
r = x/y
return y*sqrt(1+r*r)
end
hypot(5,2)
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hypot(6,5)
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hypot(6,0)
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*(1,2,4)
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function foo(a,b)
a+b, a*b
end
foo(2,3)
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x,y = foo(2,3); x
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y
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## compound expressions
# single expression evaluates several subexpressions
# returns the value of last expression
x = begin
a = 1
b = 2
a+b
end
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x
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# Another way to write the same thing
p = (d = 1; e = 2; d + e)
p
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# Yet another way
q = begin g1 = 1; h = 2; g1 + h end
q
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## Conditional evaluation
a = 10
b = 20
function test(a,b)
if a < b
println("a is less than b")
elseif a == b
println("a is equal to b")
else
println("a is not less than b")
end
end
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test(10,20)
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test(20,10)
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test (10, 10)
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## if blocks are leaky and you can use new variables within if
function test2(x,y)
if x < y
relation = "less"
elseif x == y
relation = "same"
else
relation = "more"
end
println("x is ", relation, " y")
end
test2(10, 20)
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# note the variable "relation" is defined within if block
# it can still be used outside of the if block
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# Example of chaining
x = 1; y = 2
println(x < y ? "less than" : "more than")
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x = 7; y = 2
println(x < y ? "less than" : "more than")
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i = 1;
while i <= 5
println(i)
i += 1
end
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## use of for
for i = 1:5
println(i)
end
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function producer()
produce("start")
for n = 1:4 # that is n has a value from 1 to 4
produce(2n) # multiple n with 2
end
produce("stop")
end;
## now, we are going to consume the values produced
p = Task(producer)
consume(p)
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consume(p)
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# what happens when we do a for loop on this?
for x in Task(producer)
println(x)
end
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function foo(n)
x = 0
for i = 1:n
x = x + 1
end
x
end
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foo(10)
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function foo(n)
x = 0
for i = 1:n
local x
x = 1
end
x
end
foo(10)
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# x need not come before
function foo(n)
f = y -> n + x + y
x = 1
f(2)
end
foo(10)
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const e
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const e = 2.71
const pi = 3.141
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methods(+)
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methods(for)
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methods("for")
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mean(Squares(100))
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25 in Squares(10)
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immutable Squares
count::Int
end
Base.start(::Squares) = 1
Base.next(S::Squares, state) = (state*state, state+1)
Base.done(S::Squares, s) = s > S.count
Base.eltype(::Type{Squares}) = Int
Base.length(S::Squares) = S.count
for i in Squares(7)
println(1)
end
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25 in Squares(10)
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mean(Squares(100))
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for i in Squares(7)
println(i)
end
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prog = "1 + 1" # julia programme starts as a string
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## parse each string such as 1+1 into an object.
# this object is called expression
expression1 = parse(prog)
expression1
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## This has three parts:
# A symbol
expression1.head
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# next, expression arguments,
expression1.args
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# third, the result type
expression1.typ
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# Another way to write the programme above,
Exp2 = Expr(:call, :+, 1, 1)
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## Expression1 and Exp2 are same, see
expression1 == Exp2 # will return true
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## Here is the data structure
datastruct = dump(Exp2)
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# ":" is a symbol
:foo
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typeof(ans)
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# Use : to create expression objectis
ex1 = :(a+b*c+1)
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typeof(ex1)
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## ehre is the structure
parse(ex1)
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ex1.head
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dump(ex1)
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eval(ex1)
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:(1+2)
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eval(ans)
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ex = :(a+b)
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eval(ex)
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a = 5; b = 10
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eval(ex)
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macro sayHello()
return :(println("Hello World"))
end
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@sayHello()
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macro sayHello(name)
return :(println("Hello ", $name))
end
@sayHello(John)
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@sayHello("John")
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const x = rand(8)
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x = rand(8)
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Float64[ 0.25 * x[i-1] for i = 2:length(x)-1]
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Pkg.status()
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julia -v
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versioninfo()
Beyond this, I am going to update Julia to version. 0.4 and update Ijulia as well. So download Julia, install, then do Pkg.add(IJulia)
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Pkg.add("RCall")
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using RCall
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Pkg.add("Interact")
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Pkg.add("Gadfly")
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Pkg.add("Pyplot")
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Pkg.add("Pycall")
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Pkg.add("PyPlot"); Pkg.add("PyCall"); Pkg.add("Winston")
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Pkg.clone("https://github.com/randy3k/RCalling.jl.git")
Pkg.build("RCalling")
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typeof(5)
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plothist(randn(1000))
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Using PyPlot
Using Gadfly
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using PyPlot
using Gadfly
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Pkg.dir()
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plot(rand(10))
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