Demo R Markdown - Tue, Dec 1, 2020

R Markdown

This is an R Markdown document. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see http://rmarkdown.rstudio.com.

You can embed an R code chunk like this:

summary(cars)
##      speed           dist       
##  Min.   : 4.0   Min.   :  2.00  
##  1st Qu.:12.0   1st Qu.: 26.00  
##  Median :15.0   Median : 36.00  
##  Mean   :15.4   Mean   : 42.98  
##  3rd Qu.:19.0   3rd Qu.: 56.00  
##  Max.   :25.0   Max.   :120.00
fit <- lm(dist ~ speed, data = cars)
fit
## 
## Call:
## lm(formula = dist ~ speed, data = cars)
## 
## Coefficients:
## (Intercept)        speed  
##     -17.579        3.932

Including Plots

You can also embed plots. See Figure 1 for example:

par(mar = c(0, 1, 0, 1))
pie(
  c(280, 60, 20),
  c('Sky', 'Sunny side of pyramid', 'Shady side of pyramid'),
  col = c('#0292D8', '#F7EA39', '#C4B632'),
  init.angle = -50, border = NA
)
A fancy pie chart.

Figure 1: A fancy pie chart. 

summary(Orange)
##  Tree       age         circumference  
##  3:7   Min.   : 118.0   Min.   : 30.0  
##  1:7   1st Qu.: 484.0   1st Qu.: 65.5  
##  5:7   Median :1004.0   Median :115.0  
##  2:7   Mean   : 922.1   Mean   :115.9  
##  4:7   3rd Qu.:1372.0   3rd Qu.:161.5  
##        Max.   :1582.0   Max.   :214.0

Some math

\(x = 0\), but with \[\begin{equation} f(x) = \sum_0^n t_i \tag{1} \end{equation}\]

Oh, and (1).

A table

R table:

knitr::kable(
  mtcars[1:6, 1:6], caption = 'A subset of mtcars.',
  table.attr = "class=\"table\"", format = "html"
)
Table 1: A subset of mtcars.
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440
Valiant 18.1 6 225 105 2.76 3.460

And MD table:

Right Left Default Center
\(x\) 12 12 12
\(y\) 123 123 123
\(z\) 1 1 1

Plotting with Python

import numpy as np
import matplotlib.pyplot as plt

a = np.arange(0, np.pi, 0.1)
plt.plot(a, np.cos(a))
A cosine function

Figure 2: A cosine function

Fig. 2 shows a common function in practice, the cosine function.

We should also be able to get some pandas dataframes working:

import pandas
import seaborn as sns

iris = sns.load_dataset('iris')
print(iris.head().to_html(classes=['table']))
sepal_length sepal_width petal_length petal_width species
0 5.1 3.5 1.4 0.2 setosa
1 4.9 3.0 1.4 0.2 setosa
2 4.7 3.2 1.3 0.2 setosa
3 4.6 3.1 1.5 0.2 setosa
4 5.0 3.6 1.4 0.2 setosa

Syntax highlighting

Let try some fancy C++17 (with retro vibes).

#include <cstdlib>
#include <iostream>
#include <set>
#include <string>
#include <iterator>

#include <tuple>

// { 
struct S {
    int n;
    std::string s;
    float d;
    bool operator<(const S& rhs) const
    {
        // compares n to rhs.n,
        // then s to rhs.s,
        // then d to rhs.d
        return std::tie(n, s, d) < std::tie(rhs.n, rhs.s, rhs.d);
    }
};
// }

int main()
{
    std::set<S> mySet;
 
    // pre C++17:
    {
        S value{42, "Test", 3.14};
        std::set<S>::iterator iter;
        bool inserted;
 
        // unpacks the return val of insert into iter and inserted
        std::tie(iter, inserted) = mySet.insert(value);

        if (inserted)
            std::cout << "Value was inserted\n";
    }
    
    // with C++17:
    {
        S value{100, "abc", 100.0};
        const auto [iter, inserted] = mySet.insert(value);
        
        if (inserted)
            std::cout << "Value(" << iter->n << ", " << iter->s << ", ...) was inserted" << "\n";
    }
}

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