diff --git a/arrays_strings/group_items/__init__.py b/arrays_strings/group_items/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/arrays_strings/group_items/group_items_challenge.ipynb b/arrays_strings/group_items/group_items_challenge.ipynb
new file mode 100644
index 0000000..869344b
--- /dev/null
+++ b/arrays_strings/group_items/group_items_challenge.ipynb
@@ -0,0 +1,158 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>This notebook was prepared by [Author](https://github.com/). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges).</i></small>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Challenge Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Implement a function that groups identical items based on their order in the list.\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)\n",
+    "* [Solution Notebook](#Solution-Notebook)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+    "* Can we use extra data structures?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* group_ordered([1,2,1,3,2])     ->     [1,1,2,2,3]\n",
+    "* group_ordered(['a','b','a')    ->     ['a','a','b']\n",
+    "* group_ordered([1,1,2,3,4,5,2,1]->     [1,1,1,2,2,3,4,5]\n",
+    "* group_ordered([1,2,3,4,3,4])   ->     [1,2,3,3,4,4]\n",
+    "* group_ordered([])              ->     []\n",
+    "* group_ordered([1])             ->     [1]\n",
+    "* group_ordered(None)            ->     None"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "Refer to the [solution notebook](https://github.com/donnemartin/interactive-coding-challenges/templates/foo_solution.ipynb).  If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "def group_ordered(list_in):\n",
+    "    # TODO: Implement me\n",
+    "    pass"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "**The following unit test is expected to fail until you solve the challenge.**"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "# %load test_group_ordered.py\n",
+    "from nose.tools import assert_equal\n",
+    "\n",
+    "\n",
+    "class TestFoo(object):\n",
+    "\n",
+    "    def test_foo(self):\n",
+    "        assert_equal(foo(None), None)\n",
+    "        assert_equal(foo(0), 0)\n",
+    "        assert_equal(foo('bar'), 'bar')\n",
+    "        print('Success: test_foo')\n",
+    "\n",
+    "def main():\n",
+    "    test = TestFoo()\n",
+    "    test.test_foo()\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Solution Notebook\n",
+    "\n",
+    "Review the [solution notebook](https://github.com/donnemartin/interactive-coding-challenges/templates/foo_solution.ipynb) for a discussion on algorithms and code solutions."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.6"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/arrays_strings/group_items/group_ordered.py b/arrays_strings/group_items/group_ordered.py
new file mode 100644
index 0000000..3de2483
--- /dev/null
+++ b/arrays_strings/group_items/group_ordered.py
@@ -0,0 +1,26 @@
+def make_order_list(list_in):
+    order_list = []
+    for item in list_in:
+        if item not in order_list:
+            order_list.append(item)
+    return order_list
+
+
+def group_ordered(list_in):
+    if list_in is None:
+        return None
+    order_list = make_order_list(list_in)
+    current = 0
+    for item in order_list:
+        search = current + 1
+        while True:
+            try:
+                if list_in[search] != item:
+                    search += 1
+                else:
+                    current += 1
+                    list_in[current], list_in[search] = list_in[search], list_in[current]
+                    search += 1
+            except IndexError:
+                break
+    return list_in
diff --git a/arrays_strings/group_items/group_ordered_challenge.ipynb b/arrays_strings/group_items/group_ordered_challenge.ipynb
new file mode 100644
index 0000000..e061433
--- /dev/null
+++ b/arrays_strings/group_items/group_ordered_challenge.ipynb
@@ -0,0 +1,140 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>This notebook was prepared by [Author](https://github.com/). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges).</i></small>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Challenge Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Implement a function that groups identical items based on their order in the list.\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)\n",
+    "* [Solution Notebook](#Solution-Notebook)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+    "* Can we use extra data structures?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* group_ordered([1,2,1,3,2])     ->     [1,1,2,2,3]\n",
+    "* group_ordered(['a','b','a')    ->     ['a','a','b']\n",
+    "* group_ordered([1,1,2,3,4,5,2,1]->     [1,1,1,2,2,3,4,5]\n",
+    "* group_ordered([])              ->     []\n",
+    "* group_ordered([1])             ->     [1]\n",
+    "* group_ordered(None)            ->     None"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "Refer to the [solution notebook](https://github.com/donnemartin/interactive-coding-challenges/templates/foo_solution.ipynb).  If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "def group_ordered(list_in):\n",
+    "    # TODO: Implement me\n",
+    "    pass"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "**The following unit test is expected to fail until you solve the challenge.**"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "%load test_group_ordered.py"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Solution Notebook\n",
+    "\n",
+    "Review the [solution notebook](https://github.com/donnemartin/interactive-coding-challenges/templates/foo_solution.ipynb) for a discussion on algorithms and code solutions."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.6"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/arrays_strings/group_items/group_ordered_solution.ipynb b/arrays_strings/group_items/group_ordered_solution.ipynb
new file mode 100644
index 0000000..b7d8b00
--- /dev/null
+++ b/arrays_strings/group_items/group_ordered_solution.ipynb
@@ -0,0 +1,166 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>This notebook was prepared by [Author](https://github.com/). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges).</i></small>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Solution Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Implement foo(val), which returns val\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+
+    "* Is it foo or bar?\n",
+    "    * foo"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* foo(val) -> val"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "Return the input, val\n",
+    "    \n",
+    "Complexity:\n",
+    "* Time: O(1)\n",
+    "* Space: O(1)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "def foo(val):\n",
+    "    return val"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Overwriting test_foo.py\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%writefile test_foo.py\n",
+    "from nose.tools import assert_equal\n",
+    "\n",
+    "\n",
+    "class TestFoo(object):\n",
+    "\n",
+    "    def test_foo(self):\n",
+    "        assert_equal(foo(None), None)\n",
+    "        assert_equal(foo(0), 0)\n",
+    "        assert_equal(foo('bar'), 'bar')\n",
+    "        print('Success: test_foo')\n",
+    "\n",
+    "def main():\n",
+    "    test = TestFoo()\n",
+    "    test.test_foo()\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Success: test_foo\n"
+     ]
+    }
+   ],
+   "source": [
+    "%run -i test_foo.py"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.10"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/arrays_strings/group_items/test_group_ordered.py b/arrays_strings/group_items/test_group_ordered.py
new file mode 100644
index 0000000..943ac67
--- /dev/null
+++ b/arrays_strings/group_items/test_group_ordered.py
@@ -0,0 +1,20 @@
+from nose.tools import assert_equal
+
+class TestFoo(object):
+
+    def test_foo(self):
+        assert_equal(group_ordered(None), None)
+        assert_equal(group_ordered([]), [])
+        assert_equal(group_ordered([1]), [1])
+        assert_equal(group_ordered([1,2,1,3,2]),[1,1,2,2,3])
+        assert_equal(group_ordered(['a','b','a']),['a','a','b'])
+        assert_equal(group_ordered([1,1,2,3,4,5,2,1]),[1,1,1,2,2,3,4,5])
+        assert_equal(group_ordered([1,2,3,4,3,4]),[1,2,3,3,4,4])
+        print('Success: test_foo')
+
+def main():
+    test = TestFoo()
+    test.test_foo()
+
+if __name__ == '__main__':
+    main()