master
Michael Murtaugh 4 years ago
parent 36134de11f
commit 42fe36dbb3

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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"https://www.nltk.org/book/\n",
"\n",
"https://www.nltk.org/book/ch00.html#natural-language-toolkit-nltk\n"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"import nltk"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"nltk.download(\"book\", download_dir=\"/usr/local/share/nltk_data\")"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"from nltk.book import *"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"text1"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"type(text1)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"from nltk.text import Text"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"Text?"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Reading Words for the Future texts\n",
"\n",
"[Chapter 3 of the NLTK book](https://www.nltk.org/book/ch03.html) discusses using your own texts using urlopen and the nltk.text.Text class.\n",
"\n",
"We can use [urllib.request.urlopen](https://docs.python.org/3/library/urllib.request.html?highlight=urlopen#urllib.request.urlopen) + pull the \"raw\" URLs of materials from the [SI13 materials on git.xpub.nl](https://git.xpub.nl/XPUB/S13-Words-for-the-Future-materials)."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"url = \"https://git.xpub.nl/XPUB/S13-Words-for-the-Future-materials/raw/branch/master/txt-essays/RESURGENCE%20Isabelle%20Stengers.txt\""
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"from urllib.request import urlopen"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"text = urlopen(url).read().decode()"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"from nltk import word_tokenize"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"tokens = word_tokenize(text)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers = nltk.text.Text(tokens)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers.concordance(\"power\")"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers.similar(\"power\")"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers.common_contexts([\"power\", \"victims\"])"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers.dispersion_plot([\"power\", \"freedom\"])"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"freq = FreqDist(stengers)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"freq"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"freq['power']"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"freq.plot(50)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"freq.plot(50, cumulative=True)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Counting Vocabulary\n",
"\n",
"## Making a function\n",
"Investigating a text as a list of words, we discover that we can compare the count of the total number of words, with the number of unique words. If we compare "
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"len(stengers)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"len(set(stengers))"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"def lexical_diversity(text):\n",
" return len(text) / len(set(text))"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"lexical_diversity(stengers)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"def percentage (count, total):\n",
" return 100 * count / total"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"percentage(4, 5)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"NB: BE CAREFUL RUNNING THE FOLLOWING LINE ... IT'S REALLY SLOW...\n",
"Not all code is equal, and just because two different methods produce the same result\n",
"doesn't mean they're equally usable in practice\n",
"\n",
"Why? because text1 (Moby Dick) is a list\n",
"and checking if (x not in text1)\n",
"has to scan the whole list of words\n",
"AND THEN this scan is done FOR EVERY WORD in the stengers text\n",
"The result is called \"order n squared\" execution, as the number of words in each text increases\n",
"the time to perform the code get EXPONENTIALLY slower\n",
"it's basically the phenomenon of nested loops on large lists.... SSSSSSSSSLLLLLLLLLOOOOOOOOOOOWWWWWWWWWWW"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"# stengers_unique = []\n",
"# for word in stengers.tokens:\n",
"# if word not in text1:\n",
"# stengers_unique.append(word)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"# stengers_unique = [x for x in stengers.tokens if x not in text1]"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"FIX: make a set based on the Moby Dick text, checking if something is in a set is VERY FAST compared to scanning a list (Order log(n) instead of n)..."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"moby = set(text1)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"\"the\" in moby"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Rather than n\\*n (n squared), the following is just n * log(n) which is *not* exponential as n gets big"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers_unique = []\n",
"for word in stengers.tokens:\n",
" if word not in moby:\n",
" stengers_unique.append(word)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"The above can also be expressed using the more compact form of a list comprehension"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers_unique = [word for word in stengers.tokens if word not in moby]"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"len(stengers_unique)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers_unique"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers_unique_text = Text(stengers_unique)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"freq = FreqDist(stengers_unique)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"freq.plot(50)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"stengers_unique_text.concordance(\"witches\")"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Increasing the default figure size"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"from IPython.core.pylabtools import figsize"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"figsize(20.0,4.8)"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.7.3"
}
},
"nbformat": 4,
"nbformat_minor": 4
}
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