update nditer tutorial

rbt-45 · Dec 2, 2017 · 312309e · 312309e
1 parent 41acf45
commit 312309e
Showing 1 changed file with 172 additions and 22 deletions.
diff --git a/numpy/nditer.ipynb b/numpy/nditer.ipynb
@@ -1,8 +1,15 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h1 style=\"color:green\" align='center'>Numpy tutorial: iterate numpy array using nditer</h1>"
+   ]
+  },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 27,
    "metadata": {
     "collapsed": true
    },
@@ -13,8 +20,10 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 26,
-   "metadata": {},
+   "execution_count": 28,
+   "metadata": {
+    "scrolled": true
+   },
    "outputs": [
     {
      "data": {
@@ -24,7 +33,7 @@
        "       [ 8,  9, 10, 11]])"
       ]
      },
-     "execution_count": 26,
+     "execution_count": 28,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -38,12 +47,94 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "<h2 style=\"color:purple\">C style ordering</h2>"
+    "<h3 style=\"color:purple\">Using normal for loop iteration</h3>"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 27,
+   "execution_count": 29,
+   "metadata": {
+    "scrolled": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "0\n",
+      "1\n",
+      "2\n",
+      "3\n",
+      "4\n",
+      "5\n",
+      "6\n",
+      "7\n",
+      "8\n",
+      "9\n",
+      "10\n",
+      "11\n"
+     ]
+    }
+   ],
+   "source": [
+    "for row in a:\n",
+    "    for cell in row:\n",
+    "        print(cell)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h3 style=\"color:purple\">For loop with flatten</h3>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "0\n",
+      "1\n",
+      "2\n",
+      "3\n",
+      "4\n",
+      "5\n",
+      "6\n",
+      "7\n",
+      "8\n",
+      "9\n",
+      "10\n",
+      "11\n"
+     ]
+    }
+   ],
+   "source": [
+    "for cell in a.flatten():\n",
+    "    print(cell)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h1 style=\"color:blue\" align=\"center\">nditer</h1>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h3 style=\"color:purple\">C style ordering</h3>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
    "metadata": {
     "scrolled": true
    },
@@ -81,9 +172,9 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 28,
+   "execution_count": 32,
    "metadata": {
-    "scrolled": true
+    "scrolled": false
    },
    "outputs": [
     {
@@ -114,37 +205,67 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "<h2 style=\"color:purple\">Modify array values while iterating</h2>"
+    "<h3 style=\"color:purple\">external_loop</h3>"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": 33,
+   "metadata": {
+    "scrolled": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[0 4 8]\n",
+      "[1 5 9]\n",
+      "[ 2  6 10]\n",
+      "[ 3  7 11]\n"
+     ]
+    }
+   ],
+   "source": [
+    "for x in np.nditer(a, flags=['external_loop'],order='F'):\n",
+    "    print(x)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<h2 style=\"color:purple\">Modify array values while iterating</h2>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 34,
    "metadata": {
     "collapsed": true
    },
    "outputs": [],
    "source": [
     "for x in np.nditer(a, op_flags=['readwrite']):\n",
-    "    x[...] = x + 1"
+    "    x[...] = x * x"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 34,
+   "execution_count": 35,
    "metadata": {
     "scrolled": true
    },
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "array([[ 1,  2,  3,  4],\n",
-       "       [ 5,  6,  7,  8],\n",
-       "       [ 9, 10, 11, 12]])"
+       "array([[  0,   1,   4,   9],\n",
+       "       [ 16,  25,  36,  49],\n",
+       "       [ 64,  81, 100, 121]])"
       ]
      },
-     "execution_count": 34,
+     "execution_count": 35,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -162,26 +283,55 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 35,
+   "execution_count": 36,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "array([[ 0,  1,  2,  3],\n",
-       "       [ 4,  5,  6,  7],\n",
-       "       [ 8,  9, 10, 11]])"
+       "array([[ 3],\n",
+       "       [ 7],\n",
+       "       [11]])"
       ]
      },
-     "execution_count": 35,
+     "execution_count": 36,
      "metadata": {},
      "output_type": "execute_result"
     }
    ],
    "source": [
-    "b = np.arange(12).reshape(3,4)\n",
+    "b = np.arange(3, 15, 4).reshape(3,1)\n",
     "b"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 37,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "0 3\n",
+      "1 3\n",
+      "4 3\n",
+      "9 3\n",
+      "16 7\n",
+      "25 7\n",
+      "36 7\n",
+      "49 7\n",
+      "64 11\n",
+      "81 11\n",
+      "100 11\n",
+      "121 11\n"
+     ]
+    }
+   ],
+   "source": [
+    "for x, y in np.nditer([a,b]):\n",
+    "    print (x,y)"
+   ]
   }
  ],
  "metadata": {
@@ -200,7 +350,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.1"
+   "version": "3.6.3"
   }
  },
  "nbformat": 4,