{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "willing-arrest",
   "metadata": {},
   "outputs": [],
   "source": [
    "# In this Python script we attempt to develop a scheme to import and then\n",
    "# process data from multiple files.\n",
    "import numpy as np "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "composed-roberts",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "3.210000\n"
     ]
    }
   ],
   "source": [
    "# Before importing multiple files, we first have to learn about some of the\n",
    "# properties of the '%' operator.  The command '%f %n' outputs the floating\n",
    "# point number n.\n",
    "print(\"%f\" %3.21)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "italic-heaven",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "                3.210000\n"
     ]
    }
   ],
   "source": [
    "# If we put a number m in front of the f, it specifies that the number\n",
    "# output should contain m characters.  In the example below, there's lots\n",
    "# of white space in front of the output.\n",
    "print(\"%24f\" %3.21)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "amazing-peninsula",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "00000000000000003.210000\n"
     ]
    }
   ],
   "source": [
    "# We can force the white space to be filled with zeros by putting a 0\n",
    "# (zero) in front of the number m.\n",
    "print(\"%024f\" %3.21)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "appointed-sellers",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "00000000000000003.210000\n",
      "00000000000000321.000000\n"
     ]
    }
   ],
   "source": [
    "# We can also specify the number of characters that should follow the\n",
    "# decimal point using .p before the f where p is a postive integer.\n",
    "print(\"%024.6f\" %3.21)\n",
    "print(\"%024.6f\" %321)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "diverse-point",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "000\n",
      "001\n",
      "002\n"
     ]
    }
   ],
   "source": [
    "# Suppose our files a labelled something like file001data.txt,\n",
    "# file002data.txt, ...  We can use %f inside a loop to make the 001,\n",
    "# 002, ...  We want our numbers to be m = 3 characters long and to have p =\n",
    "# 0 characters after the decimal place.\n",
    "for i in range(3):\n",
    "    print(\"%03.0f\" %i)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "diagnostic-variety",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "file000data.txt\n",
      "file001data.txt\n",
      "file002data.txt\n"
     ]
    }
   ],
   "source": [
    "# We combine our %f statements with additional text to create the full file\n",
    "# name.\n",
    "for i in range(3):\n",
    "    print(\"file%03.0fdata.txt\" %i)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "id": "initial-raleigh",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "file000data.txt\n",
      "file001data.txt\n",
      "file002data.txt\n"
     ]
    }
   ],
   "source": [
    "# The following acheives exactly the same output but, in my opinion, is a little\n",
    "# cleaner.\n",
    "head = \"file\"\n",
    "toe = \"data.txt\"\n",
    "for i in range(3):\n",
    "    print(head + \"%03.0f\" %i + toe)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "id": "economic-supply",
   "metadata": {},
   "outputs": [],
   "source": [
    "# We now actually load the contents of 5 sequential data files into separate arrays.\n",
    "dataArray = []\n",
    "for i in range(1, 6, 1):\n",
    "    dataArray = dataArray + [np.loadtxt(head + \"%03.0f\" %i + toe)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "id": "compact-merit",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The contents of file 1: [1.  1.1 1.2 1.3 1.4]\n",
      "The contents of file 2: [2.  2.1 2.2 2.3 2.4]\n",
      "The contents of file 3: [3.  3.1 3.2 3.3 3.4]\n",
      "The contents of file 4: [4.  4.1 4.2 4.3 4.4]\n",
      "The contents of file 5: [5.  5.1 5.2 5.3 5.4]\n"
     ]
    }
   ],
   "source": [
    "# We can examine the contents of each array.\n",
    "for i in range(5):\n",
    "    print('The contents of file ', i + 1, ': ', dataArray[i], sep = '')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "id": "amended-database",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[array([1. , 1.1, 1.2, 1.3, 1.4]),\n",
       " array([3. , 3.1, 3.2, 3.3, 3.4]),\n",
       " array([5. , 5.1, 5.2, 5.3, 5.4])]"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Maybe we only want every second file to be imported.  Only a slight\n",
    "# change to the for loop control statement is required.    \n",
    "oddData = []\n",
    "for i in range(1, 6, 2):\n",
    "    oddData = oddData + [np.loadtxt(head + \"%03.0f\" %i + toe)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "id": "together-attack",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The contents of every odd file 1: [1.  1.1 1.2 1.3 1.4]\n",
      "The contents of every odd file 3: [3.  3.1 3.2 3.3 3.4]\n",
      "The contents of every odd file 5: [5.  5.1 5.2 5.3 5.4]\n"
     ]
    }
   ],
   "source": [
    "# We can examine the contents of each odd numbered array.\n",
    "for i in range(3):\n",
    "    print('The contents of every odd file ', 2*i + 1, ': ', oddData[i], sep = '')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "id": "owned-injury",
   "metadata": {},
   "outputs": [],
   "source": [
    "# Here we import only the even files...\n",
    "evenData = []\n",
    "for i in range(2, 6, 2):\n",
    "    evenData = evenData + [np.loadtxt(head + \"%03.0f\" %i + toe)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "id": "daily-mason",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The contents of every even file 2: [2.  2.1 2.2 2.3 2.4]\n",
      "The contents of every even file 4: [4.  4.1 4.2 4.3 4.4]\n"
     ]
    }
   ],
   "source": [
    "# ... and then examine their contents.\n",
    "for i in range(2):\n",
    "    print('The contents of every even file ', 2*(i + 1), ': ', evenData[i], sep = '')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "id": "activated-luxury",
   "metadata": {},
   "outputs": [],
   "source": [
    "# If you want to select only specific files to be imported using\n",
    "# non-sequential numbers, you can do the following.\n",
    "selectedData = []\n",
    "importList = [1, 2, 3, 4, 5, 8, 12]\n",
    "for i in range(len(importList)):\n",
    "    selectedData = selectedData + [np.loadtxt(head + \"%03.0f\" %importList[i] + toe)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "id": "higher-graduate",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The contents of each selected file 01: [1.  1.1 1.2 1.3 1.4]\n",
      "The contents of each selected file 02: [2.  2.1 2.2 2.3 2.4]\n",
      "The contents of each selected file 03: [3.  3.1 3.2 3.3 3.4]\n",
      "The contents of each selected file 04: [4.  4.1 4.2 4.3 4.4]\n",
      "The contents of each selected file 05: [5.  5.1 5.2 5.3 5.4]\n",
      "The contents of each selected file 08: [8.  8.1 8.2 8.3 8.4]\n",
      "The contents of each selected file 12: [12.  12.1 12.2 12.3 12.4]\n"
     ]
    }
   ],
   "source": [
    "# The contents of the selected files.\n",
    "for i in range(len(importList)):\n",
    "    print('The contents of each selected file %02.0f' %importList[i], ': ', selectedData[i], sep = '')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "id": "internal-median",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[5.0, 5.1000000000000005, 5.2, 5.3, 5.3999999999999995]"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Now we can do calculations using the imported data.  For example, the\n",
    "# element-by-element average of the 7 imported files is:\n",
    "elementAvg = []\n",
    "for j in range(len(selectedData[0])):\n",
    "    tot = 0\n",
    "    for i in range(len(importList)):\n",
    "        tot += selectedData[i][j]\n",
    "    elementAvg += [tot/len(importList)]\n",
    "elementAvg"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "id": "complex-peripheral",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1.2, 2.2, 3.2, 4.2, 5.2, 8.2, 12.2]"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Here's the average of each individual file:\n",
    "fileAvg = []\n",
    "for i in range(len(importList)):\n",
    "    tot = 0;\n",
    "    for j in range(len(selectedData[0])):\n",
    "        tot += selectedData[i][j]\n",
    "    fileAvg += [tot/len(selectedData[0])]\n",
    "fileAvg"
   ]
  }
 ],
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