parse single channel more easily

shell.nix

@@ -6,5 +6,6 @@ pkgs.mkShell {
     rust-analyzer
     cargo-watch
     clippy
+    rustfmt
   ];
 }

src/main.rs

@@ -138,7 +138,7 @@ when using integrate mode, multiply may need to be set to a lower number.\
     println!("infraconv: Interp = {}", params.interp);
 
     let samples = interp(&samples, params.interp);
-    
+
     println!("infraconv: Samples = {}", samples.len());
 
     let out_hz = (input_hz * params.speed * params.interp as f32).round() as i32;
@@ -211,7 +211,8 @@ fn get_scale(samples: &[f64]) -> f64 {
 
 fn read_csv(file: &str, channel: usize) -> Vec<f64> {
     let csv = fs::read_to_string(file).expect("no existing input file provided");
-    csv.lines()
+    csv.trim()
+        .lines()
         .filter(|line| line.contains(',') || !csv.contains(','))
         .map(|line| {
             let values = line.split(',');
@@ -219,7 +220,11 @@ fn read_csv(file: &str, channel: usize) -> Vec<f64> {
                 .into_iter()
                 .map(|x| x.parse().unwrap())
                 .collect::<Vec<_>>();
-            values[channel]
+            if values.len() > 1 {
+                values[channel]
+            } else {
+                values[0]
+            }
         })
         .collect()
 }