Summary data science skills
Inhoud
Course 1: Introduction ............................................................................................................................. 3
1.1 Python basics ................................................................................................................................. 3
1.2 Python lists .................................................................................................................................... 3
1.3 Functions and packages................................................................................................................. 5
1.4 Numpy (Numeric Python).............................................................................................................. 6
Course 2: Intermediate python ............................................................................................................... 8
2.1 Matplotlib ...................................................................................................................................... 8
2.2 Dictionaries & pandas.................................................................................................................... 9
2.3 Logic, Control Flow and Filtering ................................................................................................. 13
2.4 Loops ........................................................................................................................................... 15
2.5 Case study: hacker statistics ........................................................................................................ 17
2.5 Summary...................................................................................................................................... 19
Course 3: DataFrames............................................................................................................................ 20
3.1 Transforming DataFrames............................................................................................................ 20
3.2 Aggregating DataFrames; Summary statistics ............................................................................. 21
3.3 Slicing and Indexing DataFrames ................................................................................................. 23
3.4 Creating and Visualizing DataFrames .......................................................................................... 25
Course 4: Supply Chain Analytics in Python .......................................................................................... 28
4.1 Basics of supply chain optimization and PuLP ............................................................................. 28
4.2 Modeling in PuLP ......................................................................................................................... 29
4.3 Solve and evaluate model ........................................................................................................... 32
4.4 Sensitivity and simulation testing of model ................................................................................ 34
Course 5: Cleaning Data in Python ........................................................................................................ 38
5.1 Common data problems .............................................................................................................. 38
5.2 Text and categorical data problems ............................................................................................. 41
5.3 Advanced data problems ............................................................................................................. 43
5.4 Record linkage ............................................................................................................................. 46
Course 6: Cluster analysis ...................................................................................................................... 49
6.1 Introduction to clustering ............................................................................................................ 49
6.2 Hierarchical Clustering ................................................................................................................. 53
6.3 K-Means clustering ...................................................................................................................... 56
6.4 Clustering in the real world ......................................................................................................... 59
,Course 7: Machine Learning with scikit-learn (model testing) .............................................................. 63
7.1 Classification ................................................................................................................................ 63
7.2 Regression ................................................................................................................................... 66
7.3 Fine-tuning your model ............................................................................................................... 68
7.4 Preprocessing and pipelines ........................................................................................................ 70
Course 8: Linear classifiers .................................................................................................................... 73
8.1 Applying logistic regression and SVM .......................................................................................... 73
8.2 Loss functions .............................................................................................................................. 75
8.3 Logistic regression ....................................................................................................................... 77
8.4 Support Vector Machines (SVMs in detail) .................................................................................. 80
,Course 1: Introduction
1.1 Python basics
iPython shell = interactive
Python script > text files > use print to generate output
Use a # to add comments in a python script
Calculator
Variables and types
• Variables: named piece of memory that can store a value.
- Syntax: name = value
Usage:
- Compute an expression's result,
- Store that result into a variable,
- And use that variable later in the program.
• Types: Type(‘variable’)
- Float Decimal number
- Integer Whole number
- Strings Text ‘’’’
- Booleans True/False
> Different behaviour using operators for different types of floats.
> When working with different types -> Convert if necessary before using operators.
1.2 Python lists
Lists; store multiple values
• Lists: Lists are used for storing small amounts of one-dimensional data containing different types.
- But, can’t use directly with arithmetical (matrix) operators (+, -, *, /, ...).
- If you need efficient arrays with arithmetic and better multidimensional tools.
• Sublists: One list can contain more sublists
, Subsetting lists (access information in a list; indexes)
• Element: The number in a list. 1.68 is the fourth element
• Index: The index of an element in the list, it starts at 0. 1.68 has index 3
> To select an element using indexing: Fam[3] gives ‘1.68’
> Negative indexes Fam[-1] gives ‘1.89’
• Slicing: Select multiple elements in a list and creating a new list
Example: fam [3:5] returns [1.68, ‘mom’] (element 3 and 4)
> [Start ; End] -> Start is included, End is excluded!
> [:4] returns indexes 0, 1, 2 and 3 (elements 1, 2, 3, 4)
> [5:] returns indexes 5, 6, 7 (elements 6, 7, 8)
Subsetting lists of lists
x = [["a", "b", "c"],
["d", "e", "f"],
["g", "h", "i"]]
X[rows][columns]
x[2][0] Returns: ‘g’ (sublist 2 , index 0)
x[2][:2] Returns: [‘g’, ‘h’] (sublist 2 , index 0 and 1)
Manipulation Lists (update lists for commands)
• Changing the elements in a list (e.g. change, add, remove elements)
1. Change: Fam [7] = 1.86 Changes the height of dad
2. Change slice: Fam [0:2] = [“Lisa”, 1.74] Changes the 0 and 1 index
3. Adding/extend: Fam + [“me”, 1.79] Adds ‘me’ and 1.79 to the list
4. Remove: del(fam[2]) Removes “emma from the list”
> Watch out because the indexes of the list have now changes!
How lists work
> x and y are the referred to the same list. > Solution: create y as a new list.
Voordelen van het kopen van samenvattingen bij Stuvia op een rij:
√ Verzekerd van kwaliteit door reviews
Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!
Snel en makkelijk kopen
Je betaalt supersnel en eenmalig met iDeal, Bancontact of creditcard voor de samenvatting. Zonder lidmaatschap.
Focus op de essentie
Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper jesmen12. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor €7,39. Je zit daarna nergens aan vast.