From 2a613ae619698212d4f77bf62281018d220bd182 Mon Sep 17 00:00:00 2001
From: tanna <tanusingh0802@outlook.com>
Date: Mon, 8 Jun 2026 13:42:44 +0530
Subject: [PATCH] feat: implement median function

---
 src/primary/median.rs | 37 +++++++++++++++++++++++++++++++++++++
 src/primary/mod.rs    |  2 ++
 2 files changed, 39 insertions(+)
 create mode 100644 src/primary/median.rs

diff --git a/src/primary/median.rs b/src/primary/median.rs
new file mode 100644
index 0000000..66687cc
--- /dev/null
+++ b/src/primary/median.rs
@@ -0,0 +1,37 @@
+/// Returns the median (middle) value of a sequence of `f64` values
+///
+/// Empty input returns `None`.
+///
+/// # Example
+/// ```
+/// use rustats::primary::median;
+///
+/// let values = [4.0, 3.0, 1.0, 3.0];
+/// let med = median(&values);
+/// assert_eq!(med, Some(3.0));
+/// ```
+
+pub fn median(values: &[f64]) -> Option<f64> {
+    if values.is_empty() {
+        return None;
+    }
+
+    let mut sorted = values.to_vec();
+    let n = sorted.len();
+
+    sorted.sort_by(|a, b| {
+        a.partial_cmp(b)
+            .expect("Median cannot be computed for NaN values!")
+    });
+
+    let m;
+    if n % 2 == 0 {
+        let i1 = n / 2;
+        m = (sorted[i1 - 1] + sorted[i1]) / 2.0;
+    } else {
+        let i2 = (n + 1) / 2;
+        m = sorted[i2 - 1];
+    }
+
+    Some(m)
+}
diff --git a/src/primary/mod.rs b/src/primary/mod.rs
index e301a63..ffe1e57 100644
--- a/src/primary/mod.rs
+++ b/src/primary/mod.rs
@@ -1,3 +1,5 @@
 pub mod mean;
+pub mod median;
 
 pub use mean::mean;
+pub use median::median;