Initial import of itertools-0.9.0.

Bug: 155309706
Change-Id: Id790c146e836f0eadfb0d8a103cbe2d226a598c3

2 files changed, 287 insertions, 0 deletions

diff --git a/examples/iris.data b/examples/iris.data
new file mode 100644
index 0000000..a3490e0
--- /dev/null
+++ b/examples/iris.data
@@ -0,0 +1,150 @@
+5.1,3.5,1.4,0.2,Iris-setosa
+4.9,3.0,1.4,0.2,Iris-setosa
+4.7,3.2,1.3,0.2,Iris-setosa
+4.6,3.1,1.5,0.2,Iris-setosa
+5.0,3.6,1.4,0.2,Iris-setosa
+5.4,3.9,1.7,0.4,Iris-setosa
+4.6,3.4,1.4,0.3,Iris-setosa
+5.0,3.4,1.5,0.2,Iris-setosa
+4.4,2.9,1.4,0.2,Iris-setosa
+4.9,3.1,1.5,0.1,Iris-setosa
+5.4,3.7,1.5,0.2,Iris-setosa
+4.8,3.4,1.6,0.2,Iris-setosa
+4.8,3.0,1.4,0.1,Iris-setosa
+4.3,3.0,1.1,0.1,Iris-setosa
+5.8,4.0,1.2,0.2,Iris-setosa
+5.7,4.4,1.5,0.4,Iris-setosa
+5.4,3.9,1.3,0.4,Iris-setosa
+5.1,3.5,1.4,0.3,Iris-setosa
+5.7,3.8,1.7,0.3,Iris-setosa
+5.1,3.8,1.5,0.3,Iris-setosa
+5.4,3.4,1.7,0.2,Iris-setosa
+5.1,3.7,1.5,0.4,Iris-setosa
+4.6,3.6,1.0,0.2,Iris-setosa
+5.1,3.3,1.7,0.5,Iris-setosa
+4.8,3.4,1.9,0.2,Iris-setosa
+5.0,3.0,1.6,0.2,Iris-setosa
+5.0,3.4,1.6,0.4,Iris-setosa
+5.2,3.5,1.5,0.2,Iris-setosa
+5.2,3.4,1.4,0.2,Iris-setosa
+4.7,3.2,1.6,0.2,Iris-setosa
+4.8,3.1,1.6,0.2,Iris-setosa
+5.4,3.4,1.5,0.4,Iris-setosa
+5.2,4.1,1.5,0.1,Iris-setosa
+5.5,4.2,1.4,0.2,Iris-setosa
+4.9,3.1,1.5,0.1,Iris-setosa
+5.0,3.2,1.2,0.2,Iris-setosa
+5.5,3.5,1.3,0.2,Iris-setosa
+4.9,3.1,1.5,0.1,Iris-setosa
+4.4,3.0,1.3,0.2,Iris-setosa
+5.1,3.4,1.5,0.2,Iris-setosa
+5.0,3.5,1.3,0.3,Iris-setosa
+4.5,2.3,1.3,0.3,Iris-setosa
+4.4,3.2,1.3,0.2,Iris-setosa
+5.0,3.5,1.6,0.6,Iris-setosa
+5.1,3.8,1.9,0.4,Iris-setosa
+4.8,3.0,1.4,0.3,Iris-setosa
+5.1,3.8,1.6,0.2,Iris-setosa
+4.6,3.2,1.4,0.2,Iris-setosa
+5.3,3.7,1.5,0.2,Iris-setosa
+5.0,3.3,1.4,0.2,Iris-setosa
+7.0,3.2,4.7,1.4,Iris-versicolor
+6.4,3.2,4.5,1.5,Iris-versicolor
+6.9,3.1,4.9,1.5,Iris-versicolor
+5.5,2.3,4.0,1.3,Iris-versicolor
+6.5,2.8,4.6,1.5,Iris-versicolor
+5.7,2.8,4.5,1.3,Iris-versicolor
+6.3,3.3,4.7,1.6,Iris-versicolor
+4.9,2.4,3.3,1.0,Iris-versicolor
+6.6,2.9,4.6,1.3,Iris-versicolor
+5.2,2.7,3.9,1.4,Iris-versicolor
+5.0,2.0,3.5,1.0,Iris-versicolor
+5.9,3.0,4.2,1.5,Iris-versicolor
+6.0,2.2,4.0,1.0,Iris-versicolor
+6.1,2.9,4.7,1.4,Iris-versicolor
+5.6,2.9,3.6,1.3,Iris-versicolor
+6.7,3.1,4.4,1.4,Iris-versicolor
+5.6,3.0,4.5,1.5,Iris-versicolor
+5.8,2.7,4.1,1.0,Iris-versicolor
+6.2,2.2,4.5,1.5,Iris-versicolor
+5.6,2.5,3.9,1.1,Iris-versicolor
+5.9,3.2,4.8,1.8,Iris-versicolor
+6.1,2.8,4.0,1.3,Iris-versicolor
+6.3,2.5,4.9,1.5,Iris-versicolor
+6.1,2.8,4.7,1.2,Iris-versicolor
+6.4,2.9,4.3,1.3,Iris-versicolor
+6.6,3.0,4.4,1.4,Iris-versicolor
+6.8,2.8,4.8,1.4,Iris-versicolor
+6.7,3.0,5.0,1.7,Iris-versicolor
+6.0,2.9,4.5,1.5,Iris-versicolor
+5.7,2.6,3.5,1.0,Iris-versicolor
+5.5,2.4,3.8,1.1,Iris-versicolor
+5.5,2.4,3.7,1.0,Iris-versicolor
+5.8,2.7,3.9,1.2,Iris-versicolor
+6.0,2.7,5.1,1.6,Iris-versicolor
+5.4,3.0,4.5,1.5,Iris-versicolor
+6.0,3.4,4.5,1.6,Iris-versicolor
+6.7,3.1,4.7,1.5,Iris-versicolor
+6.3,2.3,4.4,1.3,Iris-versicolor
+5.6,3.0,4.1,1.3,Iris-versicolor
+5.5,2.5,4.0,1.3,Iris-versicolor
+5.5,2.6,4.4,1.2,Iris-versicolor
+6.1,3.0,4.6,1.4,Iris-versicolor
+5.8,2.6,4.0,1.2,Iris-versicolor
+5.0,2.3,3.3,1.0,Iris-versicolor
+5.6,2.7,4.2,1.3,Iris-versicolor
+5.7,3.0,4.2,1.2,Iris-versicolor
+5.7,2.9,4.2,1.3,Iris-versicolor
+6.2,2.9,4.3,1.3,Iris-versicolor
+5.1,2.5,3.0,1.1,Iris-versicolor
+5.7,2.8,4.1,1.3,Iris-versicolor
+6.3,3.3,6.0,2.5,Iris-virginica
+5.8,2.7,5.1,1.9,Iris-virginica
+7.1,3.0,5.9,2.1,Iris-virginica
+6.3,2.9,5.6,1.8,Iris-virginica
+6.5,3.0,5.8,2.2,Iris-virginica
+7.6,3.0,6.6,2.1,Iris-virginica
+4.9,2.5,4.5,1.7,Iris-virginica
+7.3,2.9,6.3,1.8,Iris-virginica
+6.7,2.5,5.8,1.8,Iris-virginica
+7.2,3.6,6.1,2.5,Iris-virginica
+6.5,3.2,5.1,2.0,Iris-virginica
+6.4,2.7,5.3,1.9,Iris-virginica
+6.8,3.0,5.5,2.1,Iris-virginica
+5.7,2.5,5.0,2.0,Iris-virginica
+5.8,2.8,5.1,2.4,Iris-virginica
+6.4,3.2,5.3,2.3,Iris-virginica
+6.5,3.0,5.5,1.8,Iris-virginica
+7.7,3.8,6.7,2.2,Iris-virginica
+7.7,2.6,6.9,2.3,Iris-virginica
+6.0,2.2,5.0,1.5,Iris-virginica
+6.9,3.2,5.7,2.3,Iris-virginica
+5.6,2.8,4.9,2.0,Iris-virginica
+7.7,2.8,6.7,2.0,Iris-virginica
+6.3,2.7,4.9,1.8,Iris-virginica
+6.7,3.3,5.7,2.1,Iris-virginica
+7.2,3.2,6.0,1.8,Iris-virginica
+6.2,2.8,4.8,1.8,Iris-virginica
+6.1,3.0,4.9,1.8,Iris-virginica
+6.4,2.8,5.6,2.1,Iris-virginica
+7.2,3.0,5.8,1.6,Iris-virginica
+7.4,2.8,6.1,1.9,Iris-virginica
+7.9,3.8,6.4,2.0,Iris-virginica
+6.4,2.8,5.6,2.2,Iris-virginica
+6.3,2.8,5.1,1.5,Iris-virginica
+6.1,2.6,5.6,1.4,Iris-virginica
+7.7,3.0,6.1,2.3,Iris-virginica
+6.3,3.4,5.6,2.4,Iris-virginica
+6.4,3.1,5.5,1.8,Iris-virginica
+6.0,3.0,4.8,1.8,Iris-virginica
+6.9,3.1,5.4,2.1,Iris-virginica
+6.7,3.1,5.6,2.4,Iris-virginica
+6.9,3.1,5.1,2.3,Iris-virginica
+5.8,2.7,5.1,1.9,Iris-virginica
+6.8,3.2,5.9,2.3,Iris-virginica
+6.7,3.3,5.7,2.5,Iris-virginica
+6.7,3.0,5.2,2.3,Iris-virginica
+6.3,2.5,5.0,1.9,Iris-virginica
+6.5,3.0,5.2,2.0,Iris-virginica
+6.2,3.4,5.4,2.3,Iris-virginica
+5.9,3.0,5.1,1.8,Iris-virginica
diff --git a/examples/iris.rs b/examples/iris.rs
new file mode 100644
index 0000000..25ab373
--- /dev/null
+++ b/examples/iris.rs
@@ -0,0 +1,137 @@
+///
+/// This example parses, sorts and groups the iris dataset
+/// and does some simple manipulations.
+///
+/// Iterators and itertools functionality are used throughout.
+
+use itertools::Itertools;
+use std::collections::HashMap;
+use std::iter::repeat;
+use std::num::ParseFloatError;
+use std::str::FromStr;
+
+static DATA: &'static str = include_str!("iris.data");
+
+#[derive(Clone, Debug)]
+struct Iris {
+    name: String,
+    data: [f32; 4],
+}
+
+#[derive(Clone, Debug)]
+enum ParseError {
+    Numeric(ParseFloatError),
+    Other(&'static str),
+}
+
+impl From<ParseFloatError> for ParseError {
+    fn from(err: ParseFloatError) -> Self {
+        ParseError::Numeric(err)
+    }
+}
+
+/// Parse an Iris from a comma-separated line
+impl FromStr for Iris {
+    type Err = ParseError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut iris = Iris { name: "".into(), data: [0.; 4] };
+        let mut parts = s.split(",").map(str::trim);
+
+        // using Iterator::by_ref()
+        for (index, part) in parts.by_ref().take(4).enumerate() {
+            iris.data[index] = part.parse::<f32>()?;
+        }
+        if let Some(name) = parts.next() {
+            iris.name = name.into();
+        } else {
+            return Err(ParseError::Other("Missing name"))
+        }
+        Ok(iris)
+    }
+}
+
+fn main() {
+    // using Itertools::fold_results to create the result of parsing
+    let irises = DATA.lines()
+                     .map(str::parse)
+                     .fold_results(Vec::new(), |mut v, iris: Iris| {
+                         v.push(iris);
+                         v
+                     });
+    let mut irises = match irises {
+        Err(e) => {
+            println!("Error parsing: {:?}", e);
+            std::process::exit(1);
+        }
+        Ok(data) => data,
+    };
+
+    // Sort them and group them
+    irises.sort_by(|a, b| Ord::cmp(&a.name, &b.name));
+
+    // using Iterator::cycle()
+    let mut plot_symbols = "+ox".chars().cycle();
+    let mut symbolmap = HashMap::new();
+
+    // using Itertools::group_by
+    for (species, species_group) in &irises.iter().group_by(|iris| &iris.name) {
+        // assign a plot symbol
+        symbolmap.entry(species).or_insert_with(|| {
+            plot_symbols.next().unwrap()
+        });
+        println!("{} (symbol={})", species, symbolmap[species]);
+
+        for iris in species_group {
+            // using Itertools::format for lazy formatting
+            println!("{:>3.1}", iris.data.iter().format(", "));
+        }
+
+    }
+
+    // Look at all combinations of the four columns
+    //
+    // See https://en.wikipedia.org/wiki/Iris_flower_data_set
+    //
+    let n = 30; // plot size
+    let mut plot = vec![' '; n * n];
+
+    // using Itertools::tuple_combinations
+    for (a, b) in (0..4).tuple_combinations() {
+        println!("Column {} vs {}:", a, b);
+
+        // Clear plot
+        //
+        // using std::iter::repeat;
+        // using Itertools::set_from
+        plot.iter_mut().set_from(repeat(' '));
+
+        // using Itertools::minmax
+        let min_max = |data: &[Iris], col| {
+            data.iter()
+                .map(|iris| iris.data[col])
+                .minmax()
+                .into_option()
+                .expect("Can't find min/max of empty iterator")
+        };
+        let (min_x, max_x) = min_max(&irises, a);
+        let (min_y, max_y) = min_max(&irises, b);
+
+        // Plot the data points
+        let round_to_grid = |x, min, max| ((x - min) / (max - min) * ((n - 1) as f32)) as usize;
+        let flip = |ix| n - 1 - ix; // reverse axis direction
+
+        for iris in &irises {
+            let ix = round_to_grid(iris.data[a], min_x, max_x);
+            let iy = flip(round_to_grid(iris.data[b], min_y, max_y));
+            plot[n * iy + ix] = symbolmap[&iris.name];
+        }
+
+        // render plot
+        //
+        // using Itertools::join
+        for line in plot.chunks(n) {
+            println!("{}", line.iter().join(" "))
+        }
+    }
+}