update IteratorPattern

Author: rambasnet

notebooks/IteratorPattern.ipynb

@@ -21,6 +21,8 @@
    "source": [
     "## Design patterns\n",
     "\n",
+    "- great resource on Refactoring, Design Patterns and Clean code - https://refactoring.guru/\n",
+    "- design patterns are a formalized way of describing a solution to a problem\n",
     "- the analogy: engineers and architects designing to build bridges, towers, buildings, and physical structures\n",
     "    - they follow certain principles to ensure structural integrity\n",
     "- design patterns are an attempt to bring this formal definition to software engineering\n",
@@ -663,7 +665,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 33,
+   "execution_count": null,
    "id": "800548c6",
    "metadata": {},
    "outputs": [
@@ -686,6 +688,8 @@
     }
    ],
    "source": [
+    "# there's a file in the data directory called system.log\n",
+    "# let's read it in using a generator expression\n",
     "! cat data/system.log"
    ]
   },
@@ -733,14 +737,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 37,
+   "execution_count": null,
    "id": "05760ea0",
    "metadata": {},
    "outputs": [],
    "source": [
     "with full_log_path.open() as source:\n",
+    "    # create a generator expression that will yield lines from the log file\n",
+    "    # that contain the word 'WARN'\n",
     "    power_lines = (line for line in source if 'WARN' in line)\n",
     "    with warn_log_path.open('w') as target:\n",
+    "        # iterate over the lines to write each line to the new file\n",
     "        for line in power_lines:\n",
     "            target.write(line)"
    ]
@@ -775,7 +782,6 @@
     "\n",
     "- generator functions embody the essential features of a generator expression\n",
     "    -  which is the generalization of comprehension\n",
-    "- use regular expression to parse lines into different columns of values\n",
     "- special functions that return an iterator which returns a stream of values\n",
     "- resumable functions that can retain local variable information to resume the function where it left off\n",
     "- uses `yield` keyword to yield the next value as opposed to `return`\n",