Add -k column selector. Remove serde, use StringRecord directly to keep performance.

Author: ahcm

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "hist-cli"
-version = "0.4.3"
+version = "0.4.4"
 edition = "2021"
 authors = ["Andreas Hauser <Andreas.Hauser@LMU.de>"]
 description = "Commandline tool for plotting frequency ranked histograms of TSV/CSV data"
@@ -10,7 +10,6 @@ repository = "https://github.com/ahcm/hist-cli"
 
 [dependencies]
 plotters = "^0.3"
-serde = { version = "^1.0", features = ["derive"] }
 csv = "^1.1"
 structopt = "^0.3"
 textplots = "^0.8"

README.md

@@ -10,7 +10,7 @@ export PATH="$HOME/.cargo/bin:$PATH"
 
 ## Usage
 ```
-hist 0.4.2
+hist 0.4.4
 Plots histogram of input
 
 USAGE:
@@ -25,6 +25,7 @@ FLAGS:
 OPTIONS:
     -T, --Title <Title>          optional title above the plot [default: Counts distribution]
     -g, --geometry <geometry>    the x and y size of the plot [default: 1280x960]
+    -k, --key <key>              key (column) selector [default: 1]
     -o, --output <output>        file to save PNG plot to [default: histogram.png]
     -s, --save <save>            save counts data to file as TSV, use - for STDOUT
         --xdesc <xdesc>          x-axis label [default: Rank]

src/bin/hist.rs

@@ -1,8 +1,7 @@
 extern crate plotters;
-extern crate serde;
 extern crate csv;
+use csv::StringRecord;
 use plotters::prelude::*;
-use serde::Deserialize;
 use std::io;
 use std::collections::BTreeMap;
 use structopt::StructOpt;
@@ -19,6 +18,10 @@ struct Opt
     /// optional file with on entry per line [default: STDIN]
     input: Option<PathBuf>,
 
+    #[structopt(long, short, default_value = "1")]
+    /// key (column) selector
+    key: usize,
+
     #[structopt(parse(from_os_str), long, short, default_value = "histogram.png")]
     /// file to save PNG plot to
     output: PathBuf,
@@ -52,12 +55,6 @@ struct Opt
     ydesc: String,
 }
 
-#[derive(Debug, Deserialize)]
-struct Record
-{
-    key: String,
-}
-
 fn main() -> Result<(), Box<dyn Error>>
 {
     let opt = Opt::from_args();
@@ -72,19 +69,18 @@ fn main() -> Result<(), Box<dyn Error>>
             Box::new(io::stdin())
         };
 
-    let key_counts = 
-        csv::ReaderBuilder::new()
+    let mut reader = csv::ReaderBuilder::new()
         .has_headers(false)
         .delimiter(b'\t')
-        .from_reader(input)
-        .deserialize::<Record>()
-        .fold(BTreeMap::new(), |mut map,rec|
-        { 
-            let s = rec.unwrap().key; 
-            //*map.entry(s).or_insert(0) += 1;
-            map.entry(s).and_modify(|e| *e += 1 ).or_insert(1);
-            map
-        }); 
+        .from_reader(input);
+
+    let mut key_counts = BTreeMap::new();
+    let mut record = StringRecord::new();
+    while reader.read_record(&mut record)?
+    {
+       let s = record.get(opt.key - 1).unwrap().to_string(); 
+       key_counts.entry(s).and_modify(|e| *e += 1 ).or_insert(1);
+    }
 
     if let Some(path) = &opt.save
     {