Edit C0-A26

Author: UPstartDeveloper

chapter0-exercises/chapter_0_part2.ipynb

@@ -2125,72 +2125,183 @@
         "id": "sustainable-brunswick"
       },
       "source": [
-        "## Activity: A list of strings is given, a word is given too\n",
+        "## Activity 26: String Concatenation\n",
         "\n",
-        "- Write a Python code that inserts the word between the list elements and combine them as one single string\n",
+        "One common string operation is joining two or more strings together, to form a larger one - this is known as *concatenation*. \n",
         "\n",
-        "- Example: string1 = ['Milad', 'Amir', 'Toutounchian'] is given, 'Test' is given two. Your code should return MiladTestAmirTestToutounchian"
+        "Let's challenge your string concatenation skills: for example, say you are given a list of strings, `strings`, and another string that is just a single word - `word`.\n",
+        "\n",
+        "How would you implement Python code to concatenate the elements in `strings` together, with the `word` string placed in-between every pair of elements in the output?"
       ],
       "id": "sustainable-brunswick"
     },
+    {
+      "cell_type": "markdown",
+      "metadata": {
+        "id": "JGtlRMQZKzXX"
+      },
+      "source": [
+        "### Example Input\n",
+        "\n",
+        "```\n",
+        "Input:\n",
+        "strings = [\n",
+        "  'How was work?', \n",
+        "  'day, ', \n",
+        "  'dollar.'\n",
+        "]\n",
+        "word = ' Another ' \n",
+        "\n",
+        "Output:\n",
+        "How was work? Another day, Another dollar\n",
+        "\n",
+        "Explanation:\n",
+        "The word ' Another ' is placed in between the 1st and 2nd elements in the list, as well as the 2nd and 3rd.\n",
+        "```"
+      ],
+      "id": "JGtlRMQZKzXX"
+    },
     {
       "cell_type": "code",
       "metadata": {
         "id": "hollow-passing"
       },
       "source": [
-        "string1 = ['Milad', 'Amir', 'Toutounchian']"
+        "strings = ['How was work?', 'day,', 'dollar.']\n",
+        "word = ' Another ' "
       ],
       "id": "hollow-passing",
-      "execution_count": null,
+      "execution_count": 17,
       "outputs": []
     },
     {
-      "cell_type": "code",
+      "cell_type": "markdown",
       "metadata": {
-        "id": "antique-estonia",
-        "outputId": "7a4d91e0-23ce-4f7a-b753-c1561002c8d4"
+        "id": "OL87Oy76Nqk6"
       },
       "source": [
-        "given_word = 'Test'\n",
-        "S = ''\n",
-        "for n, string in enumerate(string1):\n",
-        "    if n != (len(string1) - 1):\n",
-        "        S = S + string + given_word\n",
-        "    else:\n",
-        "        S = S + string\n",
+        "### Solution 1: Using String Addition\n",
         "\n",
-        "print(S)"
+        "Strings in Python are just another kind of iterable. Therefore, Python lets us concatenate strings with the `+` operator, and that itself will create a larger string:"
+      ],
+      "id": "OL87Oy76Nqk6"
+    },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "id": "antique-estonia"
+      },
+      "source": [
+        "def concatenate_strings_1(strings, word):\n",
+        "    # A: init the output string\n",
+        "    message = ''\n",
+        "    # B: construct the message \n",
+        "    for index, string in enumerate(strings):\n",
+        "        # add the next string to the output\n",
+        "        message = message + string\n",
+        "        # also add the word (if we haven't reached the last element yet)\n",
+        "        if index != len(strings) - 1:\n",
+        "            message = message + word\n",
+        "    # C: display the output string\n",
+        "    print(message)"
       ],
       "id": "antique-estonia",
-      "execution_count": null,
+      "execution_count": 20,
+      "outputs": []
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {
+        "id": "D0KA60YVPKMy"
+      },
+      "source": [
+        "#### Test Out Solution 1"
+      ],
+      "id": "D0KA60YVPKMy"
+    },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "colab": {
+          "base_uri": "https://localhost:8080/"
+        },
+        "id": "35SzmDUOPL6C",
+        "outputId": "b1ebd67c-44a9-4ebb-d44c-4fa8fb9e8f24"
+      },
+      "source": [
+        "concatenate_strings_1(strings, word)"
+      ],
+      "id": "35SzmDUOPL6C",
+      "execution_count": 21,
       "outputs": [
         {
           "output_type": "stream",
           "text": [
-            "MiladTestAmirTestToutounchian\n"
+            "How was work? Another day, Another dollar.\n"
           ],
           "name": "stdout"
         }
       ]
     },
+    {
+      "cell_type": "markdown",
+      "metadata": {
+        "id": "GjUaxcs_Qh08"
+      },
+      "source": [
+        "### Solution 2: Using `str.join()`\n",
+        "\n",
+        "The `str` type in Python also comes with a method to make concatenation much easier: `str.join()`.\n",
+        "\n",
+        "This method is preferred to using addition. Not only is it more Pythonic, `str.join()` is also costs less computational resources. You may read more about its syntax in the [Python documenation](https://docs.python.org/3/library/stdtypes.html#str.join).\n",
+        "\n",
+        "Please see below an example of how this works:"
+      ],
+      "id": "GjUaxcs_Qh08"
+    },
     {
       "cell_type": "code",
       "metadata": {
-        "id": "automotive-entrepreneur",
-        "outputId": "34705a9d-471d-4823-d60e-3db643d70408"
+        "id": "automotive-entrepreneur"
       },
       "source": [
-        "## easier way in Python\n",
-        "print(given_word.join(string1))"
+        "def concatenate_strings_2(strings, word): \n",
+        "    # construct + display the output string\n",
+        "    print(word.join(strings))"
       ],
       "id": "automotive-entrepreneur",
-      "execution_count": null,
+      "execution_count": 26,
+      "outputs": []
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {
+        "id": "ZgCJYZ8hS_OK"
+      },
+      "source": [
+        "#### Test Out Solution 2"
+      ],
+      "id": "ZgCJYZ8hS_OK"
+    },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "colab": {
+          "base_uri": "https://localhost:8080/"
+        },
+        "id": "h3_CUksUTFHm",
+        "outputId": "59ddb93f-233d-4db7-c9e4-120afc4d2a1a"
+      },
+      "source": [
+        "concatenate_strings_2(strings, word)"
+      ],
+      "id": "h3_CUksUTFHm",
+      "execution_count": 27,
       "outputs": [
         {
           "output_type": "stream",
           "text": [
-            "MiladTestAmirTestToutounchian\n"
+            "How was work? Another day, Another dollar.\n"
           ],
           "name": "stdout"
         }