Merge pull request #131 from ammarmallik/master

Update linear search code and write test cases

Author: ionicc

Arrays-searching/src/linear_search/linear_search.py

@@ -1,18 +1,46 @@
-#Linear search for an element 'ele' in array 'a'
-#author-@rats123
-
-def linear(a,ele):
-    for i in range(len(a)):   #for loop iterates through every single element in array
-        if ele==a[i]:         #if match is found it returns the index
-            return i
-
-
-
-    return 'Not found'
-
-
-
-##example run
-
-
-print(linear([1,2,3,4,5,6,12,23],4))
+"""
+    Linear search
+    Search Key in an Array
+    Written by: author-@rats123
+    Updated by: @ammarmallik
+"""
+
+
+def linear_search(arr, search_key):
+    """ Algorithm:
+            1. If array is empty, return -2
+            2. Iterate array and compare each value with search_key
+            3. if search_key is found, return index
+            4. Otherwise return -1
+    """
+    if arr:
+        for index, element in enumerate(arr):
+            if element == search_key:
+                return index
+
+        return -1
+
+    return -2
+
+
+def print_result(search_key, index):
+    """Returns error based on given index"""
+    errors = {
+        -1: "{} doesn't exist in array".format(search_key),
+        -2: "Array is Empty"
+    }
+    print(errors[index] if index in errors else "Index: {}".format(index))
+
+
+if __name__ == "__main__":
+    """ Test cases """
+
+    samples = [
+        {"arr": [1, 2, 3, 4, 5], "search_key": 5},
+        {"arr": [], "search_key": 5},
+        {"arr": [1, 2, 3, 4, 5], "search_key": 6}
+    ]
+
+    for item in samples:
+        index = linear_search(item.get("arr"), item.get("search_key"))
+        print_result(item.get("search_key"), index)