# Data Mining…

Some interesting stuff we learned in the course

### Using R

``````# ploting:
x<-seq(1,7,by=0.1)
plot(x,sin(x))
#
# help:
?seq
###
###
# read data from input files
setwd('/tmp') # set working directory
#
#
###
# view specific parts of the data
###
#
# view the first 5 rows
data[1:5,]    # data[rows,colums]
#
# vector:
v<-c(1,3)
#
# retrieve specific rows/columns:
data[c(1,7,21),1] # retrieves data from row nr 1,7, 21
``````

### Type of attributes (data types):

• categorical vs. numeric
• categorical (qualitative) - ip, eye color;
• nominal (no order)
• ordinal (meaningful order; rankings, grades)
• quantitative (numeric) - weight, price
• interval (there is no “true” zero; no division; calendar dates, temperature in celsius)
• ratio (there is a true zero; there is division; temperature in kelvin, length time)
• discrete vs. continuous

### Attribute type and mathematical operations:

• distinctness: =, !=
• order: > <
• multiplication: * /

• nominal : distinctness
• ordinal : distinctness, order
• ratio : all 4

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