From 3b21f9d15822453117d1e908ab97cacd8f7f39be Mon Sep 17 00:00:00 2001
From: Andrea Bastoni <bastoni@cs.unc.edu>
Date: Mon, 12 Apr 2010 23:23:50 -0400
Subject: Add IQR outliers removal

- this code is ugly C style code "transformed" in Python
  should be reworked at some point...
---
 data_analysis/statanalyzer.py | 56 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 data_analysis/statanalyzer.py

(limited to 'data_analysis/statanalyzer.py')

diff --git a/data_analysis/statanalyzer.py b/data_analysis/statanalyzer.py
new file mode 100644
index 0000000..6e096c4
--- /dev/null
+++ b/data_analysis/statanalyzer.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+
+import numpy as np
+from scipy import stats
+
+class InterQuartileRange:
+    def __init__(self, low, high, extend = False):
+        self.low = low
+        self.high = high
+        # extend is 1.5 extension of IQR
+        self.extend = extend
+
+    def remOutliers(self, vector):
+        svect = np.sort(vector)
+        q1 = stats.scoreatpercentile(svect, self.low)
+        q3 = stats.scoreatpercentile(svect, self.high)
+
+        # match the values \in svect which are closer to q[1|3]
+        # (q1, q3)
+        q1_pos = -1
+        q3_pos = -1
+        cur_pos = 0
+        for i in svect:
+            if q1_pos != -1 and q3_pos != -1:
+                break
+            if q1_pos == -1 and i > q1:
+                q1_pos = cur_pos
+            if q3_pos == -1 and q3 < i:
+                q3_pos = cur_pos
+
+            cur_pos += 1
+
+        if self.extend == True:
+            # 1.5 IQR outliers elimination
+            eiqr = (svect[q3_pos] - svect[q1_pos]) * 1.5
+            eq1 = svect[q1_pos] - eiqr
+            if eq1 < svect[0]:
+                eq1 = svect[0]
+            eq3 = svect[q3_pos] + eiqr
+            if eq3 > svect[len(svect) - 1]:
+                eq3 = svect[len(svect) - 1]
+            # match the values \in svect which are closer to eq[1|3]
+            q1_pos = -1
+            q3_pos = -1
+            cur_pos = 0
+            for i in svect:
+                if q1_pos != -1 and q3_pos != -1:
+                    break
+                if q1_pos == -1 and i > eq1:
+                    q1_pos = cur_pos
+                if q3_pos == -1 and eq3 < i:
+                    q3_pos = cur_pos
+
+                cur_pos += 1
+
+        return svect[q1_pos : q3_pos]
-- 
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