Addition to first day

Day_1/Day_1.jl

@@ -120,6 +120,41 @@ fl = 42.0
 # ╔═╡ 750bba32-e695-48f1-af70-70c94d13366b
 meaning_of_life = 42
 
+# ╔═╡ 608d4433-6e68-4f95-8581-437234b58e87
+md"""
+## Converting
+"""
+
+# ╔═╡ beadbfd3-0015-449a-b6e7-b5182b396c1d
+convert(Int64, 3.0)
+
+# ╔═╡ 552fafa4-fad5-4efe-895f-255b3ec5c858
+convert(Complex, 3.0)
+
+# ╔═╡ d11fde7f-3238-4013-bd2d-546aab0d9f9c
+# This does not work!
+# convert(Int64, 3.2)
+
+# ╔═╡ 036a2c43-dbc9-487c-96aa-94324eeb4a52
+md"""
+## Rounding
+"""
+
+# ╔═╡ 1e954726-254e-41bb-a62f-17bdc9884bee
+# We have to tell Julia explicitely what to do
+round(Int64, 3.2)
+
+# ╔═╡ d74f6c46-f5a8-4720-bcaf-936f1508efda
+round(π)
+
+# ╔═╡ 3e5daca6-5aa8-42bf-988b-c09fb17388df
+# ; marks the start of keyword arguments. More about it later!
+round(π; digits=2)
+
+# ╔═╡ 7ff20c67-58d5-4095-bb8e-7ab7522791c7
+# You can provide a rounding mode, see the docs!
+round(π, RoundUp)
+
 # ╔═╡ 4a00035f-a1d1-409f-b73b-07f9073dc9d5
 md"""
 ## Boolean operators
@@ -164,6 +199,230 @@ split(new_to_julia, ",")
 # ╔═╡ a96f3ae9-12df-4df8-85da-09b9b1e47de1
 join(["Hello", "brave", "new", "world", "!"], " ", "")
 
+# ╔═╡ 8d106ad2-5f92-4138-bfff-56ee21e098fa
+multi_line_string = """Line 1
+Line 2
+Line 3"""
+
+# ╔═╡ f8bc4051-93c6-4376-abaa-7b4cb4b8f607
+println(multi_line_string)
+
+# ╔═╡ b25dc5f2-e186-4da1-b045-47b22c93799b
+md"""
+## String formatting
+"""
+
+# ╔═╡ e0d7fbc8-39fc-4b70-9b92-0c19fffb0c05
+a
+
+# ╔═╡ 398648e8-358e-4289-ae95-957e77d0c46f
+b
+
+# ╔═╡ 28fa32e7-4e50-4890-a765-5cfb1d3f791b
+a_mult_b = a * b
+
+# ╔═╡ d2607457-1794-4a0f-af41-cb80aadb598f
+"The result of $a * $b is $a_mult_b"
+
+# ╔═╡ 23dbbe13-d997-4f9f-a300-7cb78c4fb8ee
+"The result of $a * $b is $(a * b)"
+
+# ╔═╡ e767971a-7e1d-4a78-88d7-03e4ae4d51db
+# Using the macro @show, helpful for usage in scripts
+@show a * b
+
+# ╔═╡ 9e3f698d-e57b-46c2-98e0-157fa7b06ae6
+md"""
+## Arrays
+An array is a **mutable** **ordered** collection of elements.
+
+Arrays can have one dimension (vector), two dimensions (matrix) or more (tensor).
+"""
+
+# ╔═╡ d1680205-a8eb-4ef6-ae4f-059e7a30f5c1
+md"""
+### Vectors
+"""
+
+# ╔═╡ b54ace0e-8947-46a3-842a-05b5cbfc4e87
+first_vector = [2, 4, 6, 8, 10]
+
+# ╔═╡ 8c47710f-1ed2-40fd-9290-374b498380e3
+first_vector[1]
+
+# ╔═╡ a03b46cc-1b26-44c2-b83d-884e3dbbe4fa
+md"""
+Yes, it is not the second element of the vector! 😯
+
+In Julia, indexing starts with 1️⃣
+"""
+
+# ╔═╡ 68658408-188e-43f7-ad74-251172dec0a8
+# ⚠️ This results in an error!
+# first_vector[0]
+
+# ╔═╡ 45b64c7a-850b-402c-b7ce-2a0bf6d77060
+# ⚠️ No negative indexing, too!
+# first_vector[-1]
+
+# ╔═╡ d1ed1515-cd59-4e10-a15c-b64325bc44c2
+# Instead, this can be used
+first_vector[end-1]
+
+# ╔═╡ 7c00f22c-860f-4bb1-b4b4-74c5c3c70f45
+# Last element
+first_vector[end]
+
+# ╔═╡ 6c80e009-30de-4232-9a1b-ac954242a5a6
+md"""
+### Slicing
+"""
+
+# ╔═╡ b1426df5-a083-4977-a72c-81e03fd7719d
+# start:end
+first_vector[2:end]
+
+# ╔═╡ 5b16ca43-1f56-4934-a420-5ffa5ed437ec
+# start:step:end
+first_vector[1:2:end]
+
+# ╔═╡ 628852dc-16e5-4a03-93a9-be209b1e8fb4
+# List of indices
+first_vector[[1, end, 2]]
+
+# ╔═╡ 3ea54f0d-2aa5-47a3-bbc3-92023a56b834
+md"""
+### Mutation
+"""
+
+# ╔═╡ e9e117af-1194-4d64-94a8-3e9fd51498aa
+# Setting the first element to 3
+begin
+	second_vector = [1, 2, 3]
+	second_vector[1] = 42
+	second_vector
+end
+
+# ╔═╡ 027313d6-c247-43e9-872b-c3f0fe71b733
+third_vector = [1, 2, 3]
+
+# ╔═╡ e77e7ceb-31e3-4231-9923-f62b1382a2d1
+# ⚠️ This does not work!
+# third_vector[2] = 42.1
+
+# ╔═╡ 65d3ddc2-36ed-4126-9211-e838ffc0d859
+typeof(third_vector)
+
+# ╔═╡ 641e8c05-3e80-47e5-be77-91090a5f799a
+begin
+	mixed_vector = ["hi", 2.1, 55.7]
+	mixed_vector[2] = 1 + 2im
+	mixed_vector
+end
+
+# ╔═╡ 2b9a5867-ca82-4a27-a700-bd0bd6c89bbe
+typeof(mixed_vector)
+
+# ╔═╡ 87b43f26-7437-4ee9-9b83-5b21e86dd0c9
+md"""
+⚠️ Try to avoid using mixed arrays (type `Any`)!
+
+It hurts the performance! 🐢
+
+This is because the array can contain anything and the compiler can not optimize for specific types.
+"""
+
+# ╔═╡ 22f5ebc1-fd5c-4ee7-b169-8144fbd9b570
+# ⚠️ This does not work! Run it and see the helpful error message
+# first_vector[1:2] = 5
+
+# ╔═╡ 7479c420-2e04-4fe7-823c-3fde9efb54ca
+# Instead use this to change many slices in the original vector
+first_vector[1:2] .= 5
+
+# ╔═╡ 4cd82256-be63-4db1-b2af-82a1358f4881
+# Compare the output of the cell above with this. What is the difference?
+typeof(first_vector[1:2])
+
+# ╔═╡ 605ee405-ec83-4064-adc8-861d95513e5e
+md"""
+### Views
+Views are not a copy of an array, but a reference to a part of it.
+"""
+
+# ╔═╡ 22a7baee-6533-43f7-8503-e5d5537a8c78
+begin
+	v = [3, 6, 9, 12]
+	@show v
+	
+	@show copy_of_v = v[1:3]
+
+	@show view_of_v = view(v, 1:3)
+
+	println()
+
+	new_value = 100
+	v[1] = new_value
+	println("Changed first element of v to $new_value")
+
+	@show v
+	@show copy_of_v
+	@show view_of_v
+
+	println()
+	
+	new_value = 42
+	copy_of_v[2] = new_value
+	println("Changed second element of copy_of_v to $new_value")
+
+	@show v
+	@show copy_of_v
+	@show view_of_v
+
+	println()
+	
+	new_value = 55
+	view_of_v[3] = new_value
+	println("Changed third element of view_of_v to $new_value")
+
+	@show v
+	@show copy_of_v
+	@show view_of_v
+end
+
+# ╔═╡ 2ac5d431-1a4d-4db2-8954-97e011cd2175
+md"""
+### Matrices
+"""
+
+# ╔═╡ d30b3a5f-e14c-45ea-89a4-cf710733a2ee
+# Readable method to define a matrix
+first_matrix = [
+1 2
+3 4
+]
+
+# ╔═╡ 6bb730e4-b5aa-4e7b-9ccd-9298db061e7f
+# Easier to write method
+second_matrix = [1 2; 3 4]
+
+# ╔═╡ 83eca43d-2280-40f1-bf2a-016a843362a3
+first_tensor = zeros(3, 3, 3)
+
+# ╔═╡ 64e47c03-356c-4a71-b463-4c247ea861cb
+first_tensor[1, 1, 1] = 1.0
+
+# ╔═╡ 23bdd308-3efa-49fd-9dcd-d4d1989383ee
+first_tensor[2, :, :] .= 4.0
+
+# ╔═╡ 1a0b5604-fa4b-4291-baf0-97340aff9bca
+first_tensor
+
+# ╔═╡ f4c48701-d90e-48d6-bf9d-539c7fb7c7a5
+md"""
+Of course, you can have more than 3 dimensions!
+"""
+
 # ╔═╡ 00000000-0000-0000-0000-000000000001
 PLUTO_PROJECT_TOML_CONTENTS = """
 [deps]
@@ -405,6 +664,15 @@ uuid = "3f19e933-33d8-53b3-aaab-bd5110c3b7a0"
 # ╠═10fdb32f-b66f-4c4e-abd9-e856549941b8
 # ╠═00ba151b-a741-448d-b8bf-775217250915
 # ╠═750bba32-e695-48f1-af70-70c94d13366b
+# ╟─608d4433-6e68-4f95-8581-437234b58e87
+# ╠═beadbfd3-0015-449a-b6e7-b5182b396c1d
+# ╠═552fafa4-fad5-4efe-895f-255b3ec5c858
+# ╠═d11fde7f-3238-4013-bd2d-546aab0d9f9c
+# ╟─036a2c43-dbc9-487c-96aa-94324eeb4a52
+# ╠═1e954726-254e-41bb-a62f-17bdc9884bee
+# ╠═d74f6c46-f5a8-4720-bcaf-936f1508efda
+# ╠═3e5daca6-5aa8-42bf-988b-c09fb17388df
+# ╠═7ff20c67-58d5-4095-bb8e-7ab7522791c7
 # ╟─4a00035f-a1d1-409f-b73b-07f9073dc9d5
 # ╠═d4ebb324-fa31-4058-9da1-35e07a971106
 # ╠═f8259580-5a29-4a13-811f-c91d6811a291
@@ -416,6 +684,49 @@ uuid = "3f19e933-33d8-53b3-aaab-bd5110c3b7a0"
 # ╠═da5fb1f9-2a2d-4148-8ba5-8c4a529829e9
 # ╠═943da836-384d-4774-aaf4-54c27feb53d8
 # ╠═a96f3ae9-12df-4df8-85da-09b9b1e47de1
+# ╠═8d106ad2-5f92-4138-bfff-56ee21e098fa
+# ╠═f8bc4051-93c6-4376-abaa-7b4cb4b8f607
+# ╟─b25dc5f2-e186-4da1-b045-47b22c93799b
+# ╠═e0d7fbc8-39fc-4b70-9b92-0c19fffb0c05
+# ╠═398648e8-358e-4289-ae95-957e77d0c46f
+# ╠═28fa32e7-4e50-4890-a765-5cfb1d3f791b
+# ╠═d2607457-1794-4a0f-af41-cb80aadb598f
+# ╠═23dbbe13-d997-4f9f-a300-7cb78c4fb8ee
+# ╠═e767971a-7e1d-4a78-88d7-03e4ae4d51db
+# ╠═9e3f698d-e57b-46c2-98e0-157fa7b06ae6
+# ╟─d1680205-a8eb-4ef6-ae4f-059e7a30f5c1
+# ╠═b54ace0e-8947-46a3-842a-05b5cbfc4e87
+# ╠═8c47710f-1ed2-40fd-9290-374b498380e3
+# ╟─a03b46cc-1b26-44c2-b83d-884e3dbbe4fa
+# ╠═68658408-188e-43f7-ad74-251172dec0a8
+# ╠═45b64c7a-850b-402c-b7ce-2a0bf6d77060
+# ╠═d1ed1515-cd59-4e10-a15c-b64325bc44c2
+# ╠═7c00f22c-860f-4bb1-b4b4-74c5c3c70f45
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+# ╠═5b16ca43-1f56-4934-a420-5ffa5ed437ec
+# ╠═628852dc-16e5-4a03-93a9-be209b1e8fb4
+# ╟─3ea54f0d-2aa5-47a3-bbc3-92023a56b834
+# ╠═e9e117af-1194-4d64-94a8-3e9fd51498aa
+# ╠═027313d6-c247-43e9-872b-c3f0fe71b733
+# ╠═e77e7ceb-31e3-4231-9923-f62b1382a2d1
+# ╠═65d3ddc2-36ed-4126-9211-e838ffc0d859
+# ╠═641e8c05-3e80-47e5-be77-91090a5f799a
+# ╠═2b9a5867-ca82-4a27-a700-bd0bd6c89bbe
+# ╠═87b43f26-7437-4ee9-9b83-5b21e86dd0c9
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+# ╠═7479c420-2e04-4fe7-823c-3fde9efb54ca
+# ╠═4cd82256-be63-4db1-b2af-82a1358f4881
+# ╠═605ee405-ec83-4064-adc8-861d95513e5e
+# ╠═22a7baee-6533-43f7-8503-e5d5537a8c78
+# ╟─2ac5d431-1a4d-4db2-8954-97e011cd2175
+# ╠═d30b3a5f-e14c-45ea-89a4-cf710733a2ee
+# ╠═6bb730e4-b5aa-4e7b-9ccd-9298db061e7f
+# ╠═83eca43d-2280-40f1-bf2a-016a843362a3
+# ╠═64e47c03-356c-4a71-b463-4c247ea861cb
+# ╠═23bdd308-3efa-49fd-9dcd-d4d1989383ee
+# ╠═1a0b5604-fa4b-4291-baf0-97340aff9bca
+# ╟─f4c48701-d90e-48d6-bf9d-539c7fb7c7a5
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