Commit 3cbcb7bb authored by Frank Hellmann's avatar Frank Hellmann
Browse files

Working on Notebook for D2 AM1

parent 4bd06b8f
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Functions, modules and all that\n",
"\n",
"In this session we will look at how to structure our code. We will\n",
"\n",
"* write functions and module\n",
"* put them under version control\n",
"* test our functions and modules (assert)\n",
"* document our functions\n",
"* write a simple script and call it from bash\n",
"* look at errors and tracebacks that tell us what went wrong\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Writing functions\n",
"\n",
"The function syntax in Python is straightforward. There are two types of arguments, positional followed by keyword arguments."
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"def fahrenheit_to_kelvin(temperature, verbose=False):\n",
" temp_in_kelvin = (temperature - 32) * 5/9 + 273.15\n",
" if verbose:\n",
" print(f\"The temperature {temperature}F equals {temp_in_kelvin:0.5}K.\")\n",
" # print(\"The temperature {}F equals {}K.\".format(temperature, temp_in_kelvin))\n",
" return temp_in_kelvin"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The temperature 30F equals 272.04K.\n"
]
},
{
"data": {
"text/plain": [
"272.0388888888889"
]
},
"execution_count": 2,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"fahrenheit_to_kelvin(30, verbose=True)"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"data": {
"text/plain": [
"272.0388888888889"
]
},
"execution_count": 3,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"fahrenheit_to_kelvin(30)"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The temperature 30F equals 272.04K.\n"
]
},
{
"data": {
"text/plain": [
"272.0388888888889"
]
},
"execution_count": 4,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"fahrenheit_to_kelvin(30, True)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"* Arguments are identified either by position or by keyword. All positional arguments come before all keyword arguments. This holds for both, declaring and calling the function."
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"def the_count(one, two, three, four=4, five=5, six=6):\n",
" print(f\"One : {one}\")\n",
" print(f\"Two : {two}\")\n",
" print(f\"Three: {three}\")\n",
" print(f\"Four : {four}\")\n",
" print(f\"Five : {five}\")\n",
" print(f\"Six : {six}\")"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"One : 10\n",
"Two : 2\n",
"Three: 3\n",
"Four : 4\n",
"Five : 5\n",
"Six : 30\n"
]
}
],
"source": [
"the_count(10,2,3,4,five=5,six=30)"
]
},
{
"cell_type": "code",
"execution_count": 7,
"metadata": {
"collapsed": false
},
"outputs": [
{
"ename": "TypeError",
"evalue": "the_count() got multiple values for argument 'four'",
"output_type": "error",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
"\u001b[0;31mTypeError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m<ipython-input-7-29bc3fadc58a>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mthe_count\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;36m10\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;36m2\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;36m3\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;36m4\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0mfour\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0;36m5\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0msix\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0;36m30\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mTypeError\u001b[0m: the_count() got multiple values for argument 'four'"
]
}
],
"source": [
"the_count(10,2,3,4,four=5,six=30)"
]
},
{
"cell_type": "code",
"execution_count": 8,
"metadata": {
"collapsed": false
},
"outputs": [
{
"ename": "SyntaxError",
"evalue": "positional argument follows keyword argument (<ipython-input-8-ee7e83d88a59>, line 1)",
"output_type": "error",
"traceback": [
"\u001b[0;36m File \u001b[0;32m\"<ipython-input-8-ee7e83d88a59>\"\u001b[0;36m, line \u001b[0;32m1\u001b[0m\n\u001b[0;31m the_count(10,2,3,4,five=5,30)\u001b[0m\n\u001b[0m ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m positional argument follows keyword argument\n"
]
}
],
"source": [
"the_count(10,2,3,4,five=5,30)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"An aside on integer division, in python 2 integer division worked differently. It always rounded down to the nearest integer. The Python 2 behavior can still be accessed via double slash:"
]
},
{
"cell_type": "code",
"execution_count": 9,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Python 3 5/9 == 0.556\n",
"Python 3 5//9 == 0\n",
"Python 2 5/9 == 0\n"
]
}
],
"source": [
"print(f\"Python 3 5/9 == {5/9:0.3}\")\n",
"print(f\"Python 3 5//9 == {5//9}\")\n",
"print(f\"Python 2 5/9 == {5//9}\")"
]
},
{
"cell_type": "code",
"execution_count": 10,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"def kelvin_to_celsius(temperature):\n",
" return temperature - 273.15"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Using functions we have defined in new functions works as expected:"
]
},
{
"cell_type": "code",
"execution_count": 11,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"def fahrenheit_to_celsius(temperature):\n",
" temp_in_kelvin = fahrenheit_to_kelvin(temperature)\n",
" return kelvin_to_celsius(temp_in_kelvin)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Functional stuff\n",
"* you can pass functions as parameters\n",
"* (and much more that we can't cover here)"
]
},
{
"cell_type": "code",
"execution_count": 12,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"f2c = fahrenheit_to_celsius"
]
},
{
"cell_type": "code",
"execution_count": 13,
"metadata": {
"collapsed": false
},
"outputs": [
{
"data": {
"text/plain": [
"-6.666666666666686"
]
},
"execution_count": 13,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"f2c(20)"
]
},
{
"cell_type": "code",
"execution_count": 14,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"def convert_many(function, temperatures):\n",
" result = list()\n",
" for t in temperatures:\n",
" result.append(function(t))\n",
" return result"
]
},
{
"cell_type": "code",
"execution_count": 15,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"[-12.222222222222229, -5.0, 4.444444444444457, -23.333333333333343]\n",
"[-12.222222222222229, -5.0, 4.444444444444457, -23.333333333333343]\n"
]
}
],
"source": [
"temp_record_fahr = [10., 23., 40., -10.]\n",
"print(convert_many(f2c, temp_record_fahr))\n",
"print(list(map(f2c, temp_record_fahr)))"
]
},
{
"cell_type": "code",
"execution_count": 16,
"metadata": {
"collapsed": false
},
"outputs": [],
"source": [
"import numpy as np"
]
},
{
"cell_type": "code",
"execution_count": 17,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"1\n",
"(4,)\n"
]
}
],
"source": [
"temp_record_fahr = np.array([10., 23., 40., -10.])\n",
"print(temp_record_fahr.ndim)\n",
"print(temp_record_fahr.shape)"
]
},
{
"cell_type": "code",
"execution_count": 18,
"metadata": {
"collapsed": false
},
"outputs": [
{
"data": {
"text/plain": [
"array([-12.22222222, -5. , 4.44444444, -23.33333333])"
]
},
"execution_count": 18,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"np.apply_along_axis(f2c, 0, temp_record_fahr)"
]
},
{
"cell_type": "code",
"execution_count": 25,
"metadata": {
"collapsed": false,
"scrolled": true
},
"outputs": [],
"source": [
"%matplotlib notebook\n",
"import pandas as pd"
]
},
{
"cell_type": "code",
"execution_count": 26,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"global_temp_anomaly = pd.read_pickle(\"global_temp_anomaly.pd\")"
]
},
{
"cell_type": "code",
"execution_count": 27,
"metadata": {
"collapsed": false
},
"outputs": [
{
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" alert('Your browser does not have WebSocket support.' +\n",
" 'Please try Chrome, Safari or Firefox ≥ 6. ' +\n",
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