I can't seem to update the style in a dataframe in Python

Question

enter code hereFirst, I don't know Python but am using it for a team project. I followed a plaid quickstart tutorial. I was able to create a dataframe with the enter code heredata I got back, use it to create an html and generate a pdf from that. It took me HOURS! Now I want to apply some basic formatting to the data, like making amounts red if they are negative, right aligning the amount field. I have the code written, but I am not using Jupyter Lab, I am using atom. I have seen a reference to needing style.render() in order to get the changes but don't know how to do it.

This is my code which shows no changes in color in the pdf

# Execute query selecting Transactions table in Plaid database
cur.execute("SELECT description, date, amount FROM transactions")

# Fetch rows
rows = cur.fetchall()

# Close cursor
cur.close()

# Close connection
con.close

# set negative amounts to red
def color_negative_red(amount):
    color = 'red' if amount < 0 else 'black'
    return 'color: %s' % color

# dataframe
df = pd.DataFrame (rows, columns = ["Transaction Description", "Date", "Amount"])
df.style.applymap(color_negative_red)

# convert data frame to <table> and display
html = df.to_html()

text_file = open("test.html", "w")
text_file.write(html)
text_file.close()

# output to a pdf
import pdfkit
pdfkit.from_file('test.html', 'out.pdf')

# open report and pdf in a browser
import webbrowser as wb
wb.open_new_tab('file://C:/Users/Carole/dev/Plaid/quickstart/python/out.pdf')

pdf generated from test sandbox environment:

Last changes: # set negative amounts to red def color_negative_red(s): color = 'red' if s < 0 else 'black' return 'color: %s' % color html = df.style.applymap(color_negative_red).render()

pd.set_option('display.max_rows', 500)

# print DataFrame
print (df)

text_file = open("test.html", "w")
text_file.write(html)
text_file.close()

# output to a pdf
import pdfkit
pdfkit.from_file('test.html', 'out.pdf')

This was my final change to get the code to work converting the amount string to a decimal

    from re import sub
    from decimal import Decimal

    new = s.replace("$","").replace(",","")
    value = Decimal(new)

    color = 'red' if value < 0 else 'black'
    return 'color: %s' % color

Answer 1

You evaluate the style but then don't do anything with it. You can use the .render() method of the styler to get HTML output.

html = df.style.applymap(color_negative_red).render()

Note that this is not a full HTML page. It includes an HTML table and style information, but no html, head, or body tags.