Inspired by my friend’s completion of the thesis-portion of their PhD, this simple project celebrates their difficult slog over the numerous years (I think four?). We will be generating a wordcloud of their thesis… well not their thesis because we have to protect their privacy, but we are going to use something similar.
But firstly, you might be asking what is a wordcloud?
A wordcloud is a visual representation of textual data. Put simply, imagine a picture of words, the greater frequency of words present in a given text, the larger it will appear. Here is an example below of what we will be building.
What will we be using?
A tour of our tool belt will include:
- Python 3.8, of course
- Jupyterlab
We are going to use two main libraries:
- spaCy – for tokenisation of words (this will make sense when we start playing around with the words)
- wordcloud – aptly named
And here are some other libraries just to help out:
Let’s get started.
Table of Contents
Installing the non-standard libraries¶
Before we can continue we need to install the extra libraries that are not standard with Python and even Anaconda/Miniconda.
First let’s install spaCy, which requires a bit more effort to install than your standard python package.
On their own webpage, they have excellent documentation on how to install their package.
I’m using conda along with Jupyterlab in mu own environment. The following commands when entered into the Jupyterlab terminal install spaCy.
conda install -c conda-forge spacy
conda install -c conda-forge spacy-lookups-data
python -m spacy download en_core_web_sm
Next is installing wordcloud, which is a lot easier.
conda install -c conda-forge wordcloud
wordcloud has some dependancies, which can be installed:
conda install -c conda-forge pillow
conda install -c conda-forge numpy
There we have it. We should all be set up to go.
Importing the Libraries¶
Let’s start coding.
# importing and setting up libraries
import random as r
import pandas as pd
import re
import matplotlib.pyplot as plt
%matplotlib inline
plt.rcParams.update({'font.size': 22})
from wordcloud import WordCloud, STOPWORDS
import spacy
spacy.prefer_gpu()
nlp = spacy.load("en_core_web_sm") # setting up for the English language
Opening up the File¶
Earlier we talking about my friend’s thesis, we are going to use what I wrote instead. It is a fantastic masterpiece on glaucoma. I wrote it on google docs. So the first thing I go is save the essay as text file (.txt). Saving it as a text file, this will make manipulating with Python at lot easier without employing another library.
Let’s open up the file and have a look at some chracters of the text file.
file = 'shivanglaucomaessay.txt'
with open(file, 'r') as f:
text = f.read()
text[1000:1500]
't is important to identify the type of glaucoma to offer appropriate treatment.\nMechanism of Glaucoma\nIntraocular pressure (IOP) has an important role in glaucoma. To understand its mechanism of action, it is very important to look at aqueous humor production and drainage (Kass, 2005). Aqueous humour is primarily produced by active secretion at the ciliary processes of the ciliary body, mediated by aquaporins and carbonic anhydrase; the prior requiring energy and the latter requiring enzymatic a'
len(text)
37519
You can see here it is only a measly 37519 chracters. I could not imagine how many a thesis would have!
Tokenisation¶
In order to count all the words we need to take my essay and turn it into ‘tokens’. We are going to use this using spaCy.
spaCy is mainly used for Natural Language Processing (NLP). NLP is a computers way of understanding text.
You can do a lot with spaCy, but for the purpose of this project we are going to be parsing the text in this essay.
doc = nlp(text)
tokens = [token for token in doc]
r.seed(42) # ensure we get the same random selection everytime this is executed
rand_select = r.choices(tokens, k=50)
rand_select
[PACG, Once, field, (, , required, cyclophotocoagulation, ,, glaucoma, important, Kass, underlying, to, 2017, gold, iris, of, ., (, a, Current, and, of, indicates, ., visual, loss, early, Silva, resulting, of, Vision, ., ,, ,, and, 2007, treatment, of, adverse, beta, angle, to, times, loss, although, detectable, important, dynamics, on]
Cleaning up¶
You might notice some problems here:
- The cases are all different in the words. Python will look at ‘Size’ and ‘size’ as different words when we want them to be the same.
- We have punctuation included as tokens and this is not important to us
- We have ‘\n’ or newline characters that need to be removed
- We have stop words like ‘the’, ‘a’, ‘an’, etc. which are not interesting words but occur a lot and will drown out the words that we care about
- Finally, this may be hard to tell with such a small selection of words here, but plurals and different
Let’s fix this by first making the text lowercase.
lower = [_.text.lower() for _ in rand_select]
lower
['pacg',
'once',
'field',
'(',
'\n',
'required',
'cyclophotocoagulation',
',',
'glaucoma',
'important',
'kass',
'underlying',
'to',
'2017',
'gold',
'iris',
'of',
'.',
'(',
'a',
'current',
'and',
'of',
'indicates',
'.',
'visual',
'loss',
'early',
'silva',
'resulting',
'of',
'vision',
'.',
',',
',',
'and',
'2007',
'treatment',
'of',
'adverse',
'beta',
'angle',
'to',
'times',
'loss',
'although',
'detectable',
'important',
'dynamics',
'on']All lower case now. Now let’s go back to our random selection again and remove the puncuation.
nopunc = [_.text for _ in rand_select if _.pos_ != 'PUNCT']
nopunc
['PACG', 'Once', 'field', '\n', 'required', 'cyclophotocoagulation', 'glaucoma', 'important', 'Kass', 'underlying', 'to', '2017', 'gold', 'iris', 'of', 'a', 'Current', 'and', 'of', 'indicates', 'visual', 'loss', 'early', 'Silva', 'resulting', 'of', 'Vision', 'and', '2007', 'treatment', 'of', 'adverse', 'beta', 'angle', 'to', 'times', 'loss', 'although', 'detectable', 'important', 'dynamics', 'on']
Now, let’s remove the ‘\n’ or newline characters. You might have not seen this, but some are bunched together liks this ‘/n/n/n/n’ in one string. So we need to some up of removing these.
nonewline = [_.text for _ in rand_select if not '\n' in _.text]
nonewline
['PACG',
'Once',
'field',
'(',
'required',
'cyclophotocoagulation',
',',
'glaucoma',
'important',
'Kass',
'underlying',
'to',
'2017',
'gold',
'iris',
'of',
'.',
'(',
'a',
'Current',
'and',
'of',
'indicates',
'.',
'visual',
'loss',
'early',
'Silva',
'resulting',
'of',
'Vision',
'.',
',',
',',
'and',
'2007',
'treatment',
'of',
'adverse',
'beta',
'angle',
'to',
'times',
'loss',
'although',
'detectable',
'important',
'dynamics',
'on']Now that we have some up with a way of removing newline characters, next we are going to remove stopwords like ‘a’, ‘an’, ‘the’ etc.
nostopwords = [_.text for _ in rand_select if not _.is_stop]
nostopwords
['PACG',
'field',
'(',
'\n',
'required',
'cyclophotocoagulation',
',',
'glaucoma',
'important',
'Kass',
'underlying',
'2017',
'gold',
'iris',
'.',
'(',
'Current',
'indicates',
'.',
'visual',
'loss',
'early',
'Silva',
'resulting',
'Vision',
'.',
',',
',',
'2007',
'treatment',
'adverse',
'beta',
'angle',
'times',
'loss',
'detectable',
'important',
'dynamics']We have removed the uninteresting stopwords.
Next is to combine inflected words using lemmatisation.
lemmas = [str(_.lemma_) for _ in rand_select]
lemmas
['PACG',
'once',
'field',
'(',
'\n',
'require',
'cyclophotocoagulation',
',',
'glaucoma',
'important',
'Kass',
'underlying',
'to',
'2017',
'gold',
'iris',
'of',
'.',
'(',
'a',
'current',
'and',
'of',
'indicate',
'.',
'visual',
'loss',
'early',
'Silva',
'result',
'of',
'Vision',
'.',
',',
',',
'and',
'2007',
'treatment',
'of',
'adverse',
'beta',
'angle',
'to',
'time',
'loss',
'although',
'detectable',
'important',
'dynamic',
'on']The effect on lemmatisation is difficult to see since we have a small selection of words.
In the previous examples, we have done all these manipulations individually. We can actually do this all at once.
cleaned_doc = [_.lemma_.lower() for _ in doc if _.pos_ != 'PUNCT'
and '\n' not in _.text
and not _.is_stop]
r.seed(43)
r.choices(cleaned_doc, k=20)
['ultrafiltration', 'science', '2007', 'tham', 'line', '223', 'use', 'important', 'factor', 'sign', 'speak', '2015', '2016', 'value', 'optic', 'able', 'murthy', '22', 'medication', 'act']
Fun Statistics¶
Now the document has been cleaned to the best of our ability. There will always be slight imperfections but I think we have dealt with the majority.
Let’s put this into a pandas dataframe so we can make some fun plots. We can also gets some statistics, which are self-explanatory.
words = pd.DataFrame(cleaned_doc, columns=['words'])
words.head()
| words | |
|---|---|
| 0 | aco |
| 1 | id |
| 2 | 109229 |
| 3 | glaucoma |
| 4 | overview |
words.describe()
| words | |
|---|---|
| count | 3549 |
| unique | 1283 |
| top | glaucoma |
| freq | 118 |
words.value_counts().head(30) # gives the first 30 results
words glaucoma 118 iop 66 treatment 40 angle 40 important 35 risk 31 - 28 visual 27 aqueous 26 / 26 cause 25 humour 25 & 24 field 23 result 23 reduce 23 m. 22 increase 22 ophthalmology 22 patient 21 nerve 20 damage 20 2016 20 optic 19 loss 19 example 19 disease 18 j. 17 a. 17 laser 17 dtype: int64
I’m still not happy with word exclusion that we came up with before. We are still getting a number of ‘-‘, ‘/’, ‘&’ and letters ending with a period (such as ‘m.’).
These are not useful to us, so let’s do some further elimination.
We are going to create list of characters that we want to excluded ['-', '/', '&']. And we are also going to use regular expression (the re module) to eliminate the letter plus period.
exclude_char = ['-', '/', '&']
cleaned_doc_again = [_.lemma_.lower() for _ in doc if _.pos_ != 'PUNCT'
and '\n' not in _.text
and not _.is_stop
and _.text not in exclude_char
and not bool(re.search(r'^\w\.$', _.text))]
words_cleaned = pd.DataFrame(cleaned_doc_again, columns=['words'])
words_cleaned.value_counts().head(30)
words glaucoma 118 iop 66 angle 40 treatment 40 important 35 risk 31 visual 27 aqueous 26 humour 25 cause 25 result 23 field 23 reduce 23 ophthalmology 22 increase 22 patient 21 nerve 20 damage 20 2016 20 loss 19 optic 19 example 19 disease 18 laser 17 involve 17 open 16 surgery 16 factor 14 develop 13 trabeculectomy 13 dtype: int64
This is much better and I think I’m a lot more satified with the result.
Now, we can then plot this onto a graph to visualise the data.
x = words_cleaned.value_counts()
fig = plt.figure(figsize=(20,10))
graph = plt.hist(x, bins=50)
ylab = plt.ylabel('Frequency')
xlab = plt.xlabel('Number of Words')
title = plt.title('Distribution of words and how frequently they occur')
This graphs tells us that the majority of words occur infrequently as we expect, which a few outliers. Let’s build a bar chart with each of the words to compare then against each other.
x_30 = words_cleaned.value_counts().head(30)
fig = plt.figure(figsize=(20,15))
graph = plt.barh([i[0] for i in x_30.index], x_30.values)
ylab = plt.ylabel('Words')
xlab = plt.xlabel('Frequency')
title = plt.title('Comparison of frequency of top 30 words')
The Wordcloud¶
Finally, we have our clean list of words that we can manufacture into a wordcloud!
This uses the special module, wordcloud and elements of matplotlib to produce this.
We can then save this as an image to our local disk.
wordcloud = WordCloud(width = 3000, height = 2000,
random_state=1, background_color='#3F3F3F',
colormap='rainbow', collocations=False).generate(' '.join(cleaned_doc_again))
fig = plt.figure(figsize=(20, 15))
imshow = plt.imshow(wordcloud)
axis = plt.axis('off')
saveimage = wordcloud.to_file('shivanglaucomaessay.png')
And there we have it. A wordcloud of my glaucoma essay.
We can take this a step further and make this into a seperate python file called ThesisWC.py and pass it through as a function. Here is the code.
I’ve downloaded a blog I wrote about blue light protection and we can pass this through the function I have created to perform the same result.
import ThesisWC
ThesisWC.ThesisWC('shivanbluelightblog.txt')
Text Length (char): 19931