Summary

Summary Data Science 144 Practical Summaries

2 purchases

Course
Data Science 114 (DATSCI144)

Institution
Stellenbosch University (SUN)

Book
Data Science for Business

Summaries of all concepts needed in data science 144 practicals, namely RStudios. Practicals 1-5 are covered.

[Show more]

Preview 3 out of 17 pages

View example

Summarized whole book? No
Which chapters are summarized? Practicals 1 - 5
Uploaded on September 2, 2022
Number of pages 17
Written in 2022/2023
Type Summary

miaolivier16 Member since 5 year 678 documents sold

R169,00

Add to cart

Add to wishlist

100% satisfaction guarantee
Immediately available after payment
Both online and in PDF
No strings attached

Notes on tutorial I

I
scripts
A text file that holds R code

←
•

extent ion / R
•
:
- r .

projects
Places where you can keep all the files associated with a
project :
input data, scripts ,
results, graphs
>
.
Rproj
> command : Open Project

Lessons from swirl 1)

① Basic building blocks

•

store results in a variable 5+7 →
y
:

data that contains data ) numbers
•
vector : a structure ( object containing a small collection of

> create with the cc ) function

> e. g. C C 1.1
,
9 3.14 )
,

function name

function ?c
•
more info on a
particular : <
no
parenthesis
•
vectors can be used in mathematical expressions
' '
Y
'

arithmetic operators :
' ' '
•
'
+ -
n
, , ,

•

square root :
sqrtc )
•
absolute value : dbsc )

•
with vectors of the same length ,
r
simply performs the arithmetic operation element -

by -

element

if vectors of different lengths the shorter until length
'
is the
'
•
are R recycles vector it same as
,

the longer Vector
; e.
g. 2 * 2 + 100 =
2 * c ( 2,2 , 2) + C C 100
,
100
,
100 )

↓
( 1 2 3)
C , ,

CCI , 2,3 4) C (0 10 )
e.
g. ,
+
,

→ C C 1 2 3, 4) + C CO 10 0 10 )
, , , , ,

object length is not multiple of shorter object length !
"
= I 12 3 14
warning ! longer a

,② workspace and files

R provides a common API ( set of commands ) for interacting with files

•
determine current
working directory :
getwd C)

list all objects local ISC )
in workspace
•
:

•

workspace : what is loaded or created in R 's
memory that can be accessed in this session

variable then Isis throw
"
if you
"
e.
g. assigned 9 to a ×
,
will x

•
list all the files in your working directory using list .fi/esc ) or dirt )
•
use
argsl ) to see what arguments a function can take
"

directory in the working directory dir
"
•
create a current :
.
create c)

• set
your working directory to another directory :
setwdlf.name "

•
create a file in
your working directory : file create 1)
.

check if file file exists C)
•
a exists in the working directory : .

•

access information about the file : file info 1) .

items $ file .info / ) $
" "

grab specific :
operator my test R
project
•

; e.g .
.

•
rename files : file . rename / from
,
to )
•
delete a file : file remove c)
variables
.

see all
make of the file file 1
" "
)
a
copy :
copy Isc )
•

workspace :
.

in
•

provide the relative path to the file : file path .
c)
clear your workspace :
• make a platform-independent pathname : file .

path Cm
,
m )

( list Isu )
directories dir create rm =
•
to create paths / : .

•

to create nested directories ,
'
recursive '
must be set to true
'
( testdir ' '
)
'

> e.
g. dir create ( file . .
path testdirz recursive = TRUE )
, ,

③ Sequences of numbers

•

operator > : creates a sequence of
integers
e.
g.
1 : 4 throws I 23 4

e.
g. pi : 10 creates a
sequence of real numbers :
3,14 . . .

4,14 . . .
5
,
14

4 : I 4 3 2 I
e.
g. >

control
more over a
sequence seqc )
• :

increment by x :

seqcl ,
10
, by = > c)

random of numbers c 5 length 30 )
sequence y seq 10
•
: =
,
,

•
check length of a
sequence :
length c) between sand to

, of length of another sequence :
create a
sequence
◦

> 1 :
length 1)
with
seq c along my sequence )
> =
. _

seq along
( my
seq)
>
_ _

number : 40)
replicate a repcx times
•
=
,

10 )
replicate a vector
rep Coco times
•
:
, 1,23 , =

•

replicate each number a certain amount of times :
repccco 1,23 ,
,
each =D

④ Vectors

atomic vectors : one data type ,
e.
g. numeric
, logical ,
character , integer and complex
lists :
multiple data types

Logical vectors

• values : TRUE , FALSE NA
,

e.
g. num -
Vec < 1 tells us if values are smaller than 1 or not

& !
>
Logical operators !
!
= = = = =
:
, , , , , ,
◦
,
and ,
not

character vectors

•
double
quotes to distinguish character objects
between chars
space
is )
" "

(
" " "

My
"
•
C name
e.
g. , , ↓
"

)
"

join characters of the char vector into single string ( my char collapse
a
paste
◦ =
:
_

,

"

)
"

◦
concatenate :c ( my _
Char ,
m

)
" " "

join char ( world !
"

paste
"
vectors Hello
"
:
Sep
• =

, ,

⑤ Missing values

placeholder for unavailable
> NA : not available ( an
quantity )
•
create a vector
containing 1000 draws from a standard normal distribution : rnorm ( 10007

•
choose a random sample of 100 elements
combining 2 vectors : sample ( cc y 27,100) ,

•
check if elements are NA : is .naC ]

•
TRUE I

•
FALSE 0

i. SUM of TRUE and FALSE gives us the number of TRUES !

> NaN : not a number e.g .
010
,

> Inf :
infinity

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying this summary from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller miaolivier16. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy this summary for R169,00. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

69411 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy summaries for 15 years now

Start selling

Summary

Summary Data Science 144 Practical Summaries

Document information

Subjects

Connected book

Written for

Seller

Reviews received

Content preview