Fix typos in first steps
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Benjamin Uekermann
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@ -74,9 +74,9 @@ myfunction(0,5;keyword1 = "notdefault")
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1. everything before the `;` => positional, after => `kwargs`
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2. List all methods with that function name - returns two functions, due to the `b=123` optional positional argument
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:: callout-tip
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## Terminology function vs. method
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Methods are instantiations of a abstract `function`
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::: callout-tip
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Terminology function vs. method: Methods are instantiations of an abstract `function`
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:::
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```julia
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anonym = (x,y) -> x+y
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@ -95,6 +95,7 @@ myfunction(args...;kwargs...) = myotherfunction(newarg,args...;kwargs...)
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```
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#### Excourse: splatting & slurping
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Think of it as unpacking / collecting something
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```julia
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@ -105,6 +106,7 @@ a = [1,2,3]
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1. equivalent to `+(1,2,3)`
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#### elementwise-function / broadcasting
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Julia is very neat in regards of applying functions elementwise (also called broadcasting).
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```julia
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@ -153,18 +155,18 @@ And a nice sideeffect: By doing this, we get rid of any specialized "serialized"
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## Linear Algebra
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```julia
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import LinearAlgebra # <1>
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import LinearAlgebra: qr
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using LinearAlgebra # <2>
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```
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1. Requires to write `LinearAlgebra.QR(...)` to access a function
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2. `LinearAlgebra` is a `Base` package, and always available
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:: callout
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Julia typically recommends to use `using PackageNames`. Name-space polution is not a problem, as the package manager will never silently overwrite an already existing method - it will always as the user to specify in those cases (different to R: shows a warning, or Python: just does on with life as if nothing happened)
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::
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::: callout-tip
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Julia typically recommends to use `using PackageNames`. Name-space polution is not a problem, as the package manager will never silently overwrite an already existing method - it will always ask the user to specify in those cases (different to R: shows a warning, or Python: just goes on with life as if nothing happened)
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:::
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```julia
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A = Matrix{Float64}(undef,11,22) # <1>
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@ -174,8 +176,7 @@ qr(A*B)
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1. equivalent to `Array`, as `Matrix` is a convenience type-alias for `Array` with 2 dimensions. Same thing for `Vector`.
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2. the `2` of `{Float64,2}` is not mandatory
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Much more on wednesday in the lecture `LinearAlgebra`!
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Much more on Wednesday in the lecture `LinearAlgebra`!
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## Style-conventions
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@ -187,11 +188,13 @@ Much more on wednesday in the lecture `LinearAlgebra`!
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| inplace / side-effects | `endwith!()`^[A functionname ending with a `!` indicates that inplace operations will occur / side-effects are possible. This is convention only, but in 99% of cases adopted] |
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# Task 1
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Ok - lot of introduction, but I think you are ready for your first interactive task.
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Follow [Task 1 here](tasks.qmd#1) )
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Follow [Task 1 here](tasks.qmd#1).
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# Julia Basics - II
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### Strings
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## Strings
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```julia
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character = 'a'
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@ -200,7 +203,8 @@ Follow [Task 1 here](tasks.qmd#1) )
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```
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1. returns `c`
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##### characters
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### characters
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```julia
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'a':'f' #<1>
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collect('a':'f') # <2>
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@ -210,7 +214,7 @@ Follow [Task 1 here](tasks.qmd#1) )
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2. a `Array{Chars}`
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3. a `String`
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##### concatenation
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### concatenation
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```julia
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a = "one"
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@ -220,14 +224,16 @@ Follow [Task 1 here](tasks.qmd#1) )
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```
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1. Indeed, `*` and not `+` - as plus implies from algebra that `a+b == b+a` which obviously is not true for string concatenation. But `a*b !== b*a` - at least for matrices.
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##### substrings
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### substrings
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```julia
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str = "long string"
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substr = SubString(str, 1, 4)
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whereis_str = findfirst("str",str)
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```
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##### regexp
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## regexp
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```julia
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str = "any WORD written in CAPITAL?"
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occursin(r"[A-Z]+", str) # <1>
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@ -236,13 +242,15 @@ Follow [Task 1 here](tasks.qmd#1) )
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1. Returns `true`. Note the small `r` before the `r"regular expression"` - nifty!
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2. Returns a `::RegexMatch` - access via `m.match` & `m.offset` (index) - or `m.captures` / `m.offsets` if you defined capture-groups
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##### Interpolation
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## Interpolation
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```julia
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a = 123
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str = "this is a: $a; this 2*a: $(2*a)"
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```
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## Scopes
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All things (excepts modules) are in local scope (in scripts)
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``` julia
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@ -273,7 +281,7 @@ Putting this code into a function automatically resolves this issue
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:::
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#### explicit global / local
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### explicit global / local
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``` julia
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a = 0
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@ -293,7 +301,8 @@ b #<2>
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2. b = 1
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#### Modifying containers works in any case
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### Modifying containers works in any case
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```julia
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a = zeros(10)
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for k = 1:10
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@ -305,6 +314,7 @@ a #<1>
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1. This works "correctly" in the `REPL` as well as in a script, because we modify the content of `a`, not `a` itself
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## Types
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Types play a super important role in Julia for several main reasons:
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1) The allow for specialization e.g. `+(a::Int64,b::Float64)` might have a different (faster?) implementation compared to `+(a::Float64,b::Float64)`
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@ -312,6 +322,7 @@ Types play a super important role in Julia for several main reasons:
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3) They act as containers, structuring your programs and tools
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Everything in julia has a type! Check this out:
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```julia
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typeof(1)
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typeof(1.0)
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@ -340,6 +351,7 @@ And there are two more, `Singleton types` and `Parametric types` - which (at lea
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### composite types
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You can think of these types as containers for your variables, which allows you for specialization.
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```julia
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struct SimulationResults
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@ -380,6 +392,7 @@ once defined, a type-definition in the global scope of the REPL cannot be re-def
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:::
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# Task 2
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Follow [Task 2 here](tasks.qmd#2)
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# Julia Basics III
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@ -405,6 +418,7 @@ using MyStatsPackage
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```
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## Macros
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Macros allow to programmers to edit the actual code **before** it is run. We will pretty much just use them, without learning how they work.
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```julia
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@ -413,5 +427,7 @@ Macros allow to programmers to edit the actual code **before** it is run. We wil
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a = "123"
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@show a
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```
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## Debugging
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XXX
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XXX
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