{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Strings in python\n",
    "\n",
    "Import numpy etc. first. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "import matplotlib.pyplot as plt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Strings can be created and concatenated."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "This is the first part of a sentence and this is the second.\n"
     ]
    }
   ],
   "source": [
    "s1 = \"This is the first part of a sentence\"\n",
    "s2 = \"and this is the second.\"\n",
    "s = s1 + \" \" + s2\n",
    "print(s)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The method str() does it's best to convert things into strings. The method format() is useful for formatting output from programs. The brackets {} in a string are interpreted as placeholders for the quantities that appear in an appended format() statement. Quatnitites can be reformatted if the brackets contain a colon followed by a formatting command. E.g. :.5f means format as floating point number with 5 decimal places."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The value of pi is 3.141592653589793\n",
      "The value of pi is 3.14159\n"
     ]
    }
   ],
   "source": [
    "print(\"The value of pi is \" + str(np.pi))\n",
    "print(\"The value of {} is {:.5f}\".format(\"pi\",np.pi))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Can also explicitly refer to the position of the elements in the format statement. Note that you have to use 0 as the first index, as always!"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "This is the first time I have written this.\n"
     ]
    }
   ],
   "source": [
    "print(\"This is the {2} time I have written {3}{0}\".format(\".\",\"second\",\"first\",\"this\"))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The ways of formatting numbers include :b for binary, :d for decimal, :o for octal and :x for hexadecimal."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Ten is 1010 in binary.\n",
      "Ten is a in hexadecimal.\n"
     ]
    }
   ],
   "source": [
    "print(\"Ten is {:b} in binary.\".format(10))\n",
    "print(\"Ten is {:x} in hexadecimal.\".format(10))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Another way of formatting things is using the % sign. You have to indicate the type of the object to be inserted in the string, e.g. %s is a string, %.4f is a floating point number with 4 decimal places."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The value of pi is 3.1416, but some people use 3. \n"
     ]
    }
   ],
   "source": [
    "print(\"The value of %s is %.4f, \" %(\"pi\",np.pi) + \"but some people use %.d. \" %(3.0))"
   ]
  }
 ],
 "metadata": {
  "anaconda-cloud": {},
  "kernelspec": {
   "display_name": "Python [default]",
   "language": "python",
   "name": "python3"
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  "language_info": {
   "codemirror_mode": {
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