Small changes to Iris section 3.

stephenworsley · Apr 25, 2019 · 9f32da2 · 9f32da2
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Showing 2 changed files with 18 additions and 13 deletions.
diff --git a/course_content/iris_course/3.Subcube_Extraction.ipynb b/course_content/iris_course/3.Subcube_Extraction.ipynb
@@ -52,7 +52,7 @@
     "\n",
     "## 3.1 Indexing<a id='indexing'></a>\n",
     "\n",
-    "Cubes can be indexed in a familiar manner to that of NumPy arrays:"
+    "Cubes can be indexed in a similar manner to that of NumPy arrays:"
    ]
   },
   {
@@ -179,7 +179,8 @@
    "outputs": [],
    "source": [
     "cubes = iris.load(fname)\n",
-    "print(cubes.extract('air_potential_temperature'))"
+    "potential_temperature_cubes = cubes.extract('air_potential_temperature')\n",
+    "print(potential_temperature_cubes)"
    ]
   },
   {
@@ -198,7 +199,10 @@
    "outputs": [],
    "source": [
     "pot_temperature_constraint = iris.Constraint('air_potential_temperature')\n",
-    "print(cubes.extract(pot_temperature_constraint))"
+    "\n",
+    "pt2_cubes = cubes.extract(pot_temperature_constraint)\n",
+    "print(pt2_cubes)\n",
+    "print(pt2_cubes == potential_temperature_cubes)"
    ]
   },
   {
@@ -270,7 +274,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "As you may have seen in the iris.Constraint documentation, we can define arbitrary functions that operate on each cell of a coordinate. This is a common thing to do for floating point coordinates, where exact equality is non-trivial."
+    "As you may have seen in the iris.Constraint documentation, we can also make a Constraint from an arbitrary function that operates on each cell of a coordinate. This is a common thing to do for floating point coordinates, where exact equality testing is unreliable."
    ]
   },
   {
@@ -279,12 +283,13 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "def less_than_10(cell):\n",
-    "    \"\"\"Return True for values that are less than 10.\"\"\"\n",
-    "    return cell < 10\n",
+    "def near_357p5(cell):\n",
+    "    \"\"\"Return True for values close to 358.75. This will match one selected longitude point.\"\"\"\n",
+    "    return 358.74 < cell < 358.76\n",
     "\n",
-    "print(cubes.extract(iris.Constraint('air_potential_temperature',\n",
-    "                                    model_level_number=less_than_10)))"
+    "model_level_10_cubes = cubes.extract(iris.Constraint('air_potential_temperature',\n",
+    "                                    grid_longitude=near_357p5))\n",
+    "print(model_level_10_cubes)"
    ]
   },
   {
@@ -344,7 +349,7 @@
    "source": [
     "To combine different Constraints we use an `&`.\n",
     "\n",
-    "For example, below we extract a cube named `air_potential_temperature` with model level numbers 4 and 10."
+    "For example, below we extract the data named `air_potential_temperature`, *and* with model level numbers 4 and 10."
    ]
   },
   {
@@ -522,7 +527,7 @@
    "source": [
     "----\n",
     "\n",
-    "## 3.4 Exercise 3 <a id='exercise'></a>"
+    "## 3.4 Section Review Exercise <a id='exercise'></a>"
    ]
   },
   {
@@ -636,7 +641,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.6"
+   "version": "3.6.8"
   }
  },
  "nbformat": 4,

diff --git a/course_content/iris_course/solutions/iris_exercise_3.1a b/course_content/iris_course/solutions/iris_exercise_3.1a
@@ -1,5 +1,5 @@
 
 # Iris course sample answer 3.1a
-# Index of first two elements from the first dimensions.
+# Index of first two elements from the first dimension.
 
 subcube[:2]