3 - Control flow
All typical control flow (
do) are supported, and parenthesis around the condition are not necessary. Multiple conditions can be specified in the for loop, e.g.:`
for i = 1:2, j = 2:4
continueare supported and works as expected.
Julia support list comprehension and maps:
[myfunction(i) for i in [1, 2, 3]]
[x + 2y for x in [10, 20, 30], y in [1, 2, 3]]
mydict = Dict(); [mydict[i]=value for (i, value) in enumerate(mylist)](
enumeratereturns an iterator to tuples with the index and the value of elements in an array)
[students[name] = sex for (name,sex) in zip(names,sexes)](
zipreturns an iterator of tuples pairing two or multiple lists, e.g. [("Marc","M"),("Anne","F")] )
map((n,s) -> students[n] = s, names, sexes)(
mapapplies a function to a list of arguments) When mapping a function with a single parameter, the parameter can be omitted:
a = map(f, [1, 2, 3])is equal to
a = map(x->f(x), [1, 2, 3]).
Ternary operator is supported as
a ? b : c(if
ais true, then
c). Put attenction to wrap the
:operators with space.
Not to be confused with the bitwise operators
oraliases to respectively
||has not being imlemented.
Do blocks allow to define anonymous functions that are passed as first argument to the outer functions. For example,
findall(x -> x == value, myarray)expects the first argument to be a function. Every time the first argument is a function, this can be written at posteriori with a do block:
findall(myarray) do x
x == value
xas a variable that is passed to the inner contend of the
doblock. It is the task of the outer function to where to apply this anonymous function (in this case to the
myarrayarray) and what to do with its return values (in this case boolean values used for computing the indexes in the array). More infos on the do blocks: https://en.wikibooks.org/wiki/Introducing_Julia/Controlling_the_flow#Do_block , https://docs.julialang.org/en/stable/manual/functions/#Do-Block-Syntax-for-Function-Arguments-1
While an updated, expanded and revised version of this chapter is available in "Chapter 3 - Control Flow and Functions" of Antonello Lobianco (2019), "Julia Quick Syntax Reference", Apress, this tutorial remains in active development.