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Fix typos in first steps

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Benjamin Uekermann 2023-09-28 10:01:28 +02:00 committed by GitHub
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material/1_mon/firststeps/firststeps_handout.qmd
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@ -74,9 +74,9 @@ myfunction(0,5;keyword1 = "notdefault")
1. everything before the `;` => positional, after => `kwargs` 1. everything before the `;` => positional, after => `kwargs`
2. List all methods with that function name - returns two functions, due to the `b=123` optional positional argument 2. List all methods with that function name - returns two functions, due to the `b=123` optional positional argument
:: callout-tip ::: callout-tip
## Terminology function vs. method Terminology function vs. method: Methods are instantiations of an abstract `function`
Methods are instantiations of a abstract `function` :::
```julia ```julia
anonym = (x,y) -> x+y anonym = (x,y) -> x+y
@ -95,6 +95,7 @@ myfunction(args...;kwargs...) = myotherfunction(newarg,args...;kwargs...)
``` ```
#### Excourse: splatting & slurping #### Excourse: splatting & slurping
Think of it as unpacking / collecting something Think of it as unpacking / collecting something
```julia ```julia
@ -105,6 +106,7 @@ a = [1,2,3]
1. equivalent to `+(1,2,3)` 1. equivalent to `+(1,2,3)`
#### elementwise-function / broadcasting #### elementwise-function / broadcasting
Julia is very neat in regards of applying functions elementwise (also called broadcasting). Julia is very neat in regards of applying functions elementwise (also called broadcasting).
```julia ```julia
@ -153,18 +155,18 @@ And a nice sideeffect: By doing this, we get rid of any specialized "serialized"
## Linear Algebra ## Linear Algebra
```julia ```julia
import LinearAlgebra # <1> import LinearAlgebra # <1>
import LinearAlgebra: qr import LinearAlgebra: qr
using LinearAlgebra # <2> using LinearAlgebra # <2>
``` ```
1. Requires to write `LinearAlgebra.QR(...)` to access a function 1. Requires to write `LinearAlgebra.QR(...)` to access a function
2. `LinearAlgebra` is a `Base` package, and always available 2. `LinearAlgebra` is a `Base` package, and always available
:: callout ::: callout-tip
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) 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)
:: :::
```julia ```julia
A = Matrix{Float64}(undef,11,22) # <1> A = Matrix{Float64}(undef,11,22) # <1>
@ -174,8 +176,7 @@ qr(A*B)
1. equivalent to `Array`, as `Matrix` is a convenience type-alias for `Array` with 2 dimensions. Same thing for `Vector`. 1. equivalent to `Array`, as `Matrix` is a convenience type-alias for `Array` with 2 dimensions. Same thing for `Vector`.
2. the `2` of `{Float64,2}` is not mandatory 2. the `2` of `{Float64,2}` is not mandatory
Much more on Wednesday in the lecture `LinearAlgebra`!
Much more on wednesday in the lecture `LinearAlgebra`!
## Style-conventions ## Style-conventions
@ -187,11 +188,13 @@ Much more on wednesday in the lecture `LinearAlgebra`!
| 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] | | 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] |
# Task 1 # Task 1
Ok - lot of introduction, but I think you are ready for your first interactive task. Ok - lot of introduction, but I think you are ready for your first interactive task.
Follow [Task 1 here](tasks.qmd#1) ) Follow [Task 1 here](tasks.qmd#1).
# Julia Basics - II # Julia Basics - II
### Strings
## Strings
```julia ```julia
character = 'a' character = 'a'
@ -200,7 +203,8 @@ Follow [Task 1 here](tasks.qmd#1) )
``` ```
1. returns `c` 1. returns `c`
##### characters ### characters
```julia ```julia
'a':'f' #<1> 'a':'f' #<1>
collect('a':'f') # <2> collect('a':'f') # <2>
@ -210,7 +214,7 @@ Follow [Task 1 here](tasks.qmd#1) )
2. a `Array{Chars}` 2. a `Array{Chars}`
3. a `String` 3. a `String`
##### concatenation ### concatenation
```julia ```julia
a = "one" a = "one"
@ -220,14 +224,16 @@ Follow [Task 1 here](tasks.qmd#1) )
``` ```
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. 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.
##### substrings ### substrings
```julia ```julia
str = "long string" str = "long string"
substr = SubString(str, 1, 4) substr = SubString(str, 1, 4)
whereis_str = findfirst("str",str) whereis_str = findfirst("str",str)
``` ```
##### regexp ## regexp
```julia ```julia
str = "any WORD written in CAPITAL?" str = "any WORD written in CAPITAL?"
occursin(r"[A-Z]+", str) # <1> occursin(r"[A-Z]+", str) # <1>
@ -236,13 +242,15 @@ Follow [Task 1 here](tasks.qmd#1) )
1. Returns `true`. Note the small `r` before the `r"regular expression"` - nifty! 1. Returns `true`. Note the small `r` before the `r"regular expression"` - nifty!
2. Returns a `::RegexMatch` - access via `m.match` & `m.offset` (index) - or `m.captures` / `m.offsets` if you defined capture-groups 2. Returns a `::RegexMatch` - access via `m.match` & `m.offset` (index) - or `m.captures` / `m.offsets` if you defined capture-groups
##### Interpolation ## Interpolation
```julia ```julia
a = 123 a = 123
str = "this is a: $a; this 2*a: $(2*a)" str = "this is a: $a; this 2*a: $(2*a)"
``` ```
## Scopes ## Scopes
All things (excepts modules) are in local scope (in scripts) All things (excepts modules) are in local scope (in scripts)
``` julia ``` julia
@ -273,7 +281,7 @@ Putting this code into a function automatically resolves this issue
::: :::
#### explicit global / local ### explicit global / local
``` julia ``` julia
a = 0 a = 0
@ -293,7 +301,8 @@ b #<2>
2. b = 1 2. b = 1
#### Modifying containers works in any case ### Modifying containers works in any case
```julia ```julia
a = zeros(10) a = zeros(10)
for k = 1:10 for k = 1:10
@ -305,6 +314,7 @@ a #<1>
1. This works "correctly" in the `REPL` as well as in a script, because we modify the content of `a`, not `a` itself 1. This works "correctly" in the `REPL` as well as in a script, because we modify the content of `a`, not `a` itself
## Types ## Types
Types play a super important role in Julia for several main reasons: Types play a super important role in Julia for several main reasons:
1) The allow for specialization e.g. `+(a::Int64,b::Float64)` might have a different (faster?) implementation compared to `+(a::Float64,b::Float64)` 1) The allow for specialization e.g. `+(a::Int64,b::Float64)` might have a different (faster?) implementation compared to `+(a::Float64,b::Float64)`
@ -312,6 +322,7 @@ Types play a super important role in Julia for several main reasons:
3) They act as containers, structuring your programs and tools 3) They act as containers, structuring your programs and tools
Everything in julia has a type! Check this out: Everything in julia has a type! Check this out:
```julia ```julia
typeof(1) typeof(1)
typeof(1.0) typeof(1.0)
@ -340,6 +351,7 @@ And there are two more, `Singleton types` and `Parametric types` - which (at lea
### composite types ### composite types
You can think of these types as containers for your variables, which allows you for specialization. You can think of these types as containers for your variables, which allows you for specialization.
```julia ```julia
struct SimulationResults struct SimulationResults
@ -380,6 +392,7 @@ once defined, a type-definition in the global scope of the REPL cannot be re-def
::: :::
# Task 2 # Task 2
Follow [Task 2 here](tasks.qmd#2) Follow [Task 2 here](tasks.qmd#2)
# Julia Basics III # Julia Basics III
@ -405,6 +418,7 @@ using MyStatsPackage
``` ```
## Macros ## Macros
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. 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.
```julia ```julia
@ -413,5 +427,7 @@ Macros allow to programmers to edit the actual code **before** it is run. We wil
a = "123" a = "123"
@show a @show a
``` ```
## Debugging ## Debugging
XXX
XXX