IS - Skripta 1

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# Vector arithmetics
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# (+, -, *, /, ^)

# get the max value

# get the min value

# get the range of values

# calculate the sum of all elements

# calculate the product of all elements

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# Generating regular sequences
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# generate a sequence from 1 to 10

# generate a sequence from 10 to 1

# generate a sequence from 3.2 to 4.7, with a step 0.2

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# Factor values
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# create a vector and convert to factor

# print unique factor values (levels)

# specify the order of level

# print the summary

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# Missing values
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# check which values are NAs

# NaN missing value

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# Data frame
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# create a data frame

# create a data frame from existing vectors

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# Task 1
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# Create a dataframe called *co2.emissions* containing two columns: *years* (2000, 2002, 2004, 2006, 2008, 2010) and *emission* (2.7, 2.9, 4, 4.9, 5.3, 6.2).

# Answer:

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# Loading data frame from a file
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# reading a data frame from the CSV fill

# head and tail functions

# print the number of rows

# print the number of columns

# str function

# summary function

# retrieve and change column names

# remove column duration

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# Subsetting
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# get an element from the row 3, column 1

# get the third row

# get rows at positions from 3 to 6

# get rows at positions 3 and 6

# get the second column

# get the Year column

# retrieve all songs released before year 1965
# alternative

# retrieve all songs released before year 1965 with duration lower than 150 seconds
# alternative

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# Task 2
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# Print a number of songs from 1963 that last more than 2 minutes (120 seconds).

# Answer:

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# Plotting
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# create a plot for the given vectors

# include ggplot2 library

# render a plot for the given data frame (columns Year and Duration)

# render a scatter plot for Year and Duration

# render a scatter plot with custom title and axes labels

# render a bar chart displaying the number of songs in each year

# improve the previous chart so that only years with songs are shown;
# include title and axes labels


# render a line chart (Year, Duration) for the first five songs
# with specific line and points properties

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# Task 3
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# Create a line chart from a dataset *co2.emissions* (created in Task 1) with the x-axis representing the years, and the y-axis representing the values of CO2 emissions.
# Chart title should be "China CO2 Emissions" and y-axis should have a label "CO2 Emissions".

# Answer: