3-Print Formatting.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Print Formatting\n",
    "\n",
    "In this lecture we will briefly cover the various ways to format your print statements. As you code more and more, you will probably want to have print statements that can take in a variable into a printed string statement.\n",
    "\n",
    "The most basic example of a print statement is:"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### <font color='red'>Python 3 Alert!</font>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Python3 is simpler. We use the format string."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## String formatting"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The first letter is: a, the second: b, the third: c\n"
     ]
    }
   ],
   "source": [
    "print('The first letter is: {}, the second: {}, the third: {}'.format('a','b','c'))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Each parameter is indexed. We can manipulate where the argument appears in the string by using its index."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The first letter is: c, the second: b, the third: a\n"
     ]
    }
   ],
   "source": [
    "print('The first letter is: {2}, the second: {1}, the third: {0}'.format('a','b','c'))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "We can also repeat them the argument."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The first letter is: a, the second: a, the third: a\n"
     ]
    }
   ],
   "source": [
    "print('The first letter is: {0}, the second: {0}, the third: {0}'.format('a'))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Integers and Floats"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "There is no need to specify what data type we are passing in."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The number is 10, and 10, and 10\n"
     ]
    }
   ],
   "source": [
    "print('The number is {0}, and {0}, and {0}'.format(10))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Floats are really just numbers with decimals."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The number is 10.0002, and 10.0002, and 10.0002\n"
     ]
    }
   ],
   "source": [
    "print('The number is {0}, and {0}, and {0}'.format(10.00020))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Passing in 'weird' data types aka things we haven't seen yet."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We can also pass in dictionaries, lists, sets, tuples. Don't worry about what these means, they are other types of special data types that are also collections."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The number is [20202, 39394], and [20202, 39394], and [20202, 39394]\n"
     ]
    }
   ],
   "source": [
    "print('The number is {0}, and {0}, and {0}'.format([20202, 39394]))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The number is {'Tru TV': 'Chris Gethard'}, and {'Tru TV': 'Chris Gethard'}, and {'Tru TV': 'Chris Gethard'}\n"
     ]
    }
   ],
   "source": [
    "print('The number is {0}, and {0}, and {0}'.format({'Tru TV': 'Chris Gethard'}))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The number is {'Tru TV'}, and {'Tru TV'}, and {'Tru TV'}\n"
     ]
    }
   ],
   "source": [
    "print('The number is {0}, and {0}, and {0}'.format({'Tru TV'}))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The number is A$AP Ferg, and A$AP Rocky, and A$AP Ferg\n"
     ]
    }
   ],
   "source": [
    "print('The number is {0}, and {1}, and {0}'.format('A$AP Ferg', 'A$AP Rocky'))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Setting parameters\n",
    "We can set the arguments to a name and use that name inside the string"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The number is 10.0002, and 20, and 10.0002\n"
     ]
    }
   ],
   "source": [
    "print('The number is {a}, and {b}, and {a}'.format(a=10.00020, b=20))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### <font color='blue'>Python 2 Alert!</font>\n",
    "Python2 is more complicated to format strings. Python3 improved upon this."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "This is a string\n"
     ]
    }
   ],
   "source": [
    "print 'This is a string'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Strings\n",
    "You can use the %s to format strings into your print statements."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Place another string with a mod and s: STRING\n"
     ]
    }
   ],
   "source": [
    "s = 'STRING'\n",
    "print 'Place another string with a mod and s: %s' %(s)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Floating Point Numbers aka Floats\n",
    "Floating point numbers use the format %n1.n2f where the n1 is the total minimum number of digits the string should contain (these may be filled with whitespace if the entire number does not have this many digits. The n2 placeholder stands for how many numbers to show past the decimal point. Lets see some examples:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Floating point numbers: 13.14\n"
     ]
    }
   ],
   "source": [
    "print 'Floating point numbers: %1.2f' %(13.144)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Floating point numbers: 13\n"
     ]
    }
   ],
   "source": [
    "print 'Floating point numbers: %1.0f' %(13.144)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Floating point numbers: 13.14400\n"
     ]
    }
   ],
   "source": [
    "print 'Floating point numbers: %1.5f' %(13.144)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Floating point numbers:      13.14\n"
     ]
    }
   ],
   "source": [
    "print 'Floating point numbers: %10.2f' %(13.144)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Floating point numbers:                     13.14\n"
     ]
    }
   ],
   "source": [
    "print 'Floating point numbers: %25.2f' %(13.144)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Conversion Format methods.\n",
    "It should be noted that two methods %s and %r actually convert any python object to a string using two separate methods: str() and repr(). We will learn more about these functions later on in the course, but you should note you can actually pass almost any Python object with these two methods and it will work:\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Here is a number: 123.1. Here is a string: hi\n"
     ]
    }
   ],
   "source": [
    "print 'Here is a number: %s. Here is a string: %s' %(123.1,'hi')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Here is a number: 123.1. Here is a string: 'hi'\n"
     ]
    }
   ],
   "source": [
    "print 'Here is a number: %r. Here is a string: %r' %(123.1,'hi')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Multiple Formatting\n",
    "Pass a tuple to the modulo symbol to place multiple formats in your print statements:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "First: hi!, Second: 3.14, Third: 22\n"
     ]
    }
   ],
   "source": [
    "print 'First: %s, Second: %1.2f, Third: %r' %('hi!',3.14,22)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Using the string .format() method\n",
    "The best way to format objects into your strings for print statements is using the format method. The syntax is:\n",
    "\n",
    "    'String here {var1} then also {var2}'.format(var1='something1',var2='something2')\n",
    "    \n",
    "Lets see some examples:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "This is a string with an insert\n"
     ]
    }
   ],
   "source": [
    "print 'This is a string with an {p}'.format(p='insert')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "One: Hi!, Two: Hi!, Three: Hi!\n"
     ]
    }
   ],
   "source": [
    "# Multiple times:\n",
    "print 'One: {p}, Two: {p}, Three: {p}'.format(p='Hi!')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Object 1: 1, Object 2: two, Object 3: 12.3\n"
     ]
    }
   ],
   "source": [
    "# Several Objects:\n",
    "print 'Object 1: {a}, Object 2: {b}, Object 3: {c}'.format(a=1,b='two',c=12.3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "That is the basics of string formatting! Remember that Python 3 uses a print() function, not the print statement!  "
   ]
  }
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