A Mutable Log

Using Python to analyze data in a PDF file

The state university my daughter wants to study at just announced their entrance exam results via a PDF file. I wanted to get additional insights from the data, and decided it was time to use Python—I’ve got Jupyter Notebook installed on macOS—to do the data extraction and analysis.

I needed to install a few additional packages for python 3

pip3 install PyPDF2 pandas matplotlib

First, I created an empty DataFrame with the three columns I needed

import pandas as pd
columns = ['id','name', 'result']
df = pd.DataFrame(columns=columns)

Next, I extracted data from the PDF into the DataFrame

import PyPDF2
pdf_file = open('SSA1_2018_Publicacao_v3.pdf', 'rb')
read_pdf = PyPDF2.PdfFileReader(pdf_file)
number_of_pages = read_pdf.getNumPages()
k = 0
for i in range(number_of_pages):
    page = read_pdf.getPage(i)
    textData = page.extractText()
    lineList = textData.splitlines()
    for j in range(5, len(lineList) - 2, 3):
        df.loc[k] = [lineList[j], lineList[j+1], float(lineList[j+2].replace(",", "."))]
        k = k + 1

Next, I dropped the last row because it contained spurious data

df = df.drop(df.count() - 1)

Next, I sorted the DataFrame by the result column to find the top scorers

df=df.sort_values(by=['result', 'name'])

Next, I grouped students by their score to find how many had the same score as my daughter’s

df_grouped = df.groupby(by='result')['result'].count()

Finally, I plotted the grouped data—after removing students who scored 0

%matplotlib inline
import matplotlib.pyplot as plt

Plot of number of students by result