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Operator Description Examplex + y y added to x 2 + 3 = 5x – y y subtracted from x 8 – 2 = 6x * y x multiplied by y 3 * 2 = 6x / y x divided by y 10 / 5 = 2x ^ y (or x ** y) x raised to the power y 2 ^ 5 = 32x %% y remainder of x divided by y (x mod y) 7 %% 3 = 1x %/% y x divided by y but rounded down (integer divide) 7 %/% 3 = 2All these operators are vectorized. Chapter 3 shows the use of a vectorizedfunction with the paste() function, and the process works exactly the same waywith operators. By using vectorized operators, you can carry out complexcalculations with minimal code.To see how this works, consider these two vectors, which we first discuss inthe All-Star Grannies example in Chapter 3. One vector represents the number ofbaskets Granny made during the six games of the basketball season, and the otherone represents the number of baskets her friend Geraldine made:> baskets.of.Granny baskets.of.Geraldine
Suppose that Granny and Geraldine decide to raise money for the Make-A-Wish Foundation and asked people to make a donation for every basket theymade. Granny requested $120 per basket, and Geraldine asked for $145 perbasket. How do you calculate the total donations that they collected for eachgame?R makes the calculation easy. First, calculate how much each lady earned pergame, as follows:> Granny.money Geraldine.money Granny.money + Geraldine.money[1] 2165 915 770 1010 2820 1665You also could do this in one line, as follows:> baskets.of.Granny * 120 + baskets.of.Geraldine * 145[1] 2165 915 770 1010 2820 1665Controlling the order of the operationsIn the previous example, you used both a multiplication and an additionoperator. As you see from the result, R correctly multiplies all numbers beforeadding them together. For all arithmetic operators, the classic rules for the order ofoperations apply. Calculations are carried out in the following order:1. Exponentiation2. Multiplication and division in the order in which the operators arepresented3. Addition and subtraction in the order in which the operators arepresentedThe mod operator (%%) and the integer division operator (%/%) have the same
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Running code without a compilerChap
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Creating errorsCreating warningsRec
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Analyzing tablesExtracting test res
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Working with Pivot TablesUsing the
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R For Dummies ®Published byJohn Wi
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About the AuthorsAndrie de Vries: A
Page 19 and 20: my choices. Professor Bruce Hardie
Page 21 and 22: IntroductionWelcome to R For Dummie
Page 23 and 24: : The prompt symbol, >, is not part
Page 25 and 26: You want to explore new stuff. You
Page 27 and 28: Icons Used in This BookAs you read
Page 29 and 30: Chapter 1Introducing R: The Big Pic
Page 31 and 32: eferred to as “free as in beer.
Page 33 and 34: you how to move data and graphics b
Page 35 and 36: If you have experience in other lan
Page 37 and 38: variables, get to look at the built
Page 39 and 40: Below all this information is the R
Page 41 and 42: that we use it to illustrate the ex
Page 43 and 44: Starting Your First R SessionIf you
Page 45 and 46: Using R as a calculator is very int
Page 47 and 48: Sourcing a ScriptUntil now, you’v
Page 49 and 50: Finding help on functionsWe discuss
Page 51 and 52: languages, the backslash character
Page 53 and 54: Vectorizing your functionsVectorize
Page 55 and 56: print()R tells you that it needs th
Page 57 and 58: extensions that much. But using .Rh
Page 59 and 60: Choosing a clear nameWhen Joris was
Page 61 and 62: opinions, so the naming of function
Page 63 and 64: Often, you want to add a bit of ext
Page 65 and 66: all of them at the beginning of eac
Page 67 and 68: Part IIGetting Down to Work in RIn
Page 69: calculator.Vector operations: Vecto
Page 73 and 74: FunctionWhat It Doesabs(x)log(x,bas
Page 75 and 76: decision to use scientific notation
Page 77 and 78: operations in Chapter 7.Actually, o
Page 79 and 80: NaN in calculations. The outcome of
Page 81 and 82: Take a look at the vector baskets.o
Page 83 and 84: way the value is stored in memory.R
Page 85 and 86: [1] 12 4 4 6 9 3 5 3 2 2 12 9The re
Page 87 and 88: Okay, this example isn’t too impr
Page 89 and 90: R doesn’t have an Undo button, so
Page 91 and 92: x < yx baskets.of.Granny > 5[1] TR
Page 93 and 94: that value (refer to “Dealing wit
Page 95 and 96: all(). To find out whether Granny w
Page 97 and 98: You can tell quite a few things abo
Page 99 and 100: third game, and so on.The vector re
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Page 103 and 104: In this section, you take a look at
Page 105 and 106: LETTERS[24:26][1] “X” “Y”
Page 107 and 108: Creating and assigning named vector
Page 109 and 110: Similar to the way that R displays
Page 111 and 112: [1] “The quick brown FOX jumps ov
Page 113 and 114: R performs lexicographic sorting, a
Page 115 and 116: The result of grep() is a numeric v
Page 117 and 118: Suppose you have the sentence He is
Page 119 and 120: Regular expressions allow three way
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lexicographically sorted, unique va
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difference between the levels and t
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vector subsisting rules. For exampl
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table(state.region)state.regionNort
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Chapter 6Going on a Date with RIn T
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startDate xm xm[1] “2012-01-01
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Table 6-2 Some Format Codes for Dat
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As you can see, as.POSIXct() takes
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Formatting Dates and TimesTo format
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Now you know the exact time when we
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project.org/web/packages/lubridate/
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They contain only a single type of
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To get only the number of rows, you
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[1,] 1 4 7 10[2,] 2 5 8 11[3,] 3 6
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id first.matrix[-id][1] 1 2 3 4 5
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[2,] 2 5 8 11[3,] 3 4 9 12You also
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the way. You can try that out yours
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constructing a matrix second.matrix
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[2,] 4 5 6[3,] 7 8 9[4,] 10 11 12Yo
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Using the creator functionsYou can
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[2,] 5 17[3,] 8 20[4,] 11 23This re
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[1] 6Likewise, the ncol() function
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data frame with character vectors o
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section, earlier in this chapter.Ex
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As explained in the “Combining ve
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Create a matrix with two columns.Cr
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Although the row names of the data
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you, because data frames are, in fa
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You can’t use logical vectors or
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askets.nlist baskets.nlist[‘scor
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The second line contains a $, which
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Part IIICoding in RIn this part . .
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Making the scriptSuppose you want t
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There’s no way you can define in
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Luckily, this problem doesn’t occ
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addPercent
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addPercent(new.numbers)Error in x *
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list instead of using the dots.So,
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code. So, instead of giving a funct
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Instead of passing the code of the
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Using internal functionsWriting you
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weird, think again about data frame
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print.default(small.one)$a[1] 1 2$b
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can easily add a default method exa
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carry out a certain task. Many prog
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if you have only one short line of
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you do so within a function and you
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second value of the result.4. A vec
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Luckily, R allows you to write all
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VAT client switch(client, private
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3. In each round through the loop,
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workspace. This may be exactly what
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Applying functions on rows and colu
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4 6 8You can pass any arguments you
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hours public type“numeric” “l
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Chapter 10Debugging Your CodeIn Thi
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R always tells you in which code th
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If you get warning or error message
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logit() function. Even more, the tr
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When you’re in browser mode, you
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function only until the next round
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In logit(as.numeric(x)/100) : x not
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owsum.df strsplit(‘this is a sen
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If you want to know the median numb
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typing help(paste) returns help abo
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From the description of ada::update
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Getting Involved in the R Community
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can ask and answer questions on a v
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[1] “Diamonds 2” “Clubs 2”
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[1] RCurl_1.6-10.1 tools_2.14.1The
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Chapter 12Getting Data into and out
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Using the Clipboard to copy and pas
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Using special characters in escape
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‘data.frame’: 10 obs. of 9 vari
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XLConnect also can write Excel file
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These functions need a specific fil
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Working with Files and FoldersYou k
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[1] “F:/git/roxygen2/roxygen2/REA
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can confirm this by taking a close
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But in many practical situations, y
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$: The dollar-sign operator selects
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To illustrate subsetting of data fr
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customary to specify a so-called se
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Specify a logical vector, where FAL
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After a short while of writing subs
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following:> frost head(frost, 5)Al
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Figure 13-1: Different ways of comb
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function tries to identify columns
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Both data frames have a variable Na
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time, %in% is in infix operator. An
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order. Do this using the order() fu
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Sorting multiple columns in mixed o
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FUN: The function to apply (for exa
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5.843333 3.057333 3.758000 1.199333
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with(cars, tapply(mpg, list(gear, a
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+ y ~ a + b Include columns a as we
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In the world of R, people usually r
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Now you can start. First, create so
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data: A molten data frame.formula:
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Chapter 14Summarizing DataIn This C
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that benefits from being converted
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With this dataset in your workspace
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ange(cars$mpg)[1] 10.4 33.9Calculat
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As with most functions, you can sav
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Plotting histogramsTo get a clearer
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If this concept is unfamiliar to yo
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multiple variables, there’s a lot
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oxplot(mpg ~ cyl, data=cars)Figure
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Statisticians love it when they can
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You also can calculate the correlat
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with(cars, table(am, gear))3 4 5aut
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$ Var2: Factor w/ 2 levels “sick
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time specifying the margin argument
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Taking a Closer Look at Distributio
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Still, histograms leave much to the
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Now you want to do this for the tem
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Comparing Two SamplesComparing grou
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Again, you get the value for the te
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Many research questions revolve aro
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have to specify which margins you w
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str(InsectSprays)‘data.frame’:
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Checking the model tablesWith the m
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The difference between the means.Th
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The lm() function allows you to spe
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FunctionWhat It Doescoef()Returns a
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Model.anova Model.anovaAnalysis of
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predict(Model,newdata=new.cars, int
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Chapter 16Using Base GraphicsIn Thi
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The built-in R datasets are documen
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pch=21: Filled circlepch=22: Filled
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You also can use the function ablin
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It seems odd to use a plot function
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Figure 16-6: Adding main title, x-a
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Your graphic should look like Figur
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When your plot is complete, you nee
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getwd()[1] “C:/Users/Andrie”Nex
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Creating a Lattice PlotTo explore l
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Although cyl is a numeric vector, t
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into your R console.Changing Plot O
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xyplot(mpg ~ hp | factor(cyl), data
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Three-dimensional scatterplots: clo
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Notice that the function formula do
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millions of people. (The documentat
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Printing and Saving a Lattice PlotY
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Chapter 18Looking At ggplot2 Graphi
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aes() function to set up the mappin
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visual elements is the second eleme
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geom_point() Scatterplot stat_ident
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Creating line chartsTo create a lin
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Stat Description Default Geomstat_b
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Doing nothing with identitySometime
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Working with scalesIn ggplot2, scal
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Part VIThe Part of TensIn this part
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Then calculate the sum and mean for
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first supplied value as a fixed poi
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with(mtcars, length(mpg[hp > 150]))
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For example, to find the location o
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Your results should look similar to
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RGui and RStudio allow you to set t
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Reading the Package Manual and Vign
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Because the authors of R packages w
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AppendixInstalling R and RStudioBef
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a number of startup options by adap
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If you click Browse, you can select
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To access the cheat sheet specifica
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