Python: Bar chart from XML

This page shows how to use Lua to read in the data names with counts from XML text files and make a simple bar chart.

Here are links to the topic series of representing and processing data.

R examples:

Python examples:

Python: Bar chart from text and CSV
Python: Bar chart from JSON
Python: Bar chart from XML (this page)
Python: Bar chart from CSV using Pandas
Python: Bar chart from JSON using Pandas

JavaScript and D3 examples:

JavaScript: SVG bar chart using D3

Julia examples:

Julia: Bar chart from JSON data using StatsPlots

... more to be added ...

The ElementTree library is needed.

import xml.etree.ElementTree as et

An abbreviation is often used for imported libraries. In this case, the abbreviation et is used.

Here is one typical form of XML data using nodes with attributes.

Here is the Python code [#2]

import matplotlib.pyplot as plt
import numpy as np
np.random.seed(0)
import xml.etree.ElementTree as et
xmlFs1 = "./letters1.xml"
print("XML data from \"{0:s}\" using attributes:".format(xmlFs1))
xml1 = et.parse(xmlFs1)
root1 = xml1.getroot()
# Echo and transform the JSON data
print("")
print("\tLetter : Count")
print("")
dataList1 = []
for record1 in root1:
	name1 = record1.attrib["name"]
	count1 = int(record1.attrib["value"])
	dataList1.append([name1,count1])
	print("\t{0:s} : {1:,}".format(name1,count1))
# transform data into needed form
xData1 = []
yData1 = []
for name1,count1 in dataList1:
	xData1.append(name1)
	yData1.append(count1)
# set plot parameters
fontDict1 = {
	"family" : "Verdana",
	"weight" : "bold",
	"size" : 16
	}
plt.rc("font", **fontDict1)
# make the bar chart
rlen1 = 1
clen1 = 1
width1 = 1024
height1 = 360
dpi1 = 72
figsize1 = (width1/dpi1,height1/dpi1)
fig1,ax1 = plt.subplots(rlen1,clen1,figsize=figsize1,dpi=dpi1)
y_pos1 = np.arange(len(xData1))
plt.bar(y_pos1, yData1)
plt.xticks(y_pos1, xData1)
plt.ylabel("Count")
plt.xlabel("Letter")
plt.title("Count by Letter")
# save the bar chart
print("")
pngFs1 = "./count15-2-01.png"
print("{0:s} (chart as image)".format(pngFs1))
fig1.savefig(pngFs1,bbox_inches="tight")

Here is the output of the Python code.

XML data from "./letters1.xml" using attributes:
	Letter : Count
	a : 59,900
	b : 11,302
	c : 14,311
	d : 34,483
	e : 95,247
	f : 17,852
	g : 13,528
	h : 62,509
	i : 46,347
	j : 2,321
	k : 4,449
	l : 25,939
	m : 19,154
	n : 51,311
	o : 54,741
	p : 9,918
	q : 183
	r : 37,468
	s : 44,630
	t : 72,396
	u : 20,651
	v : 7,458
	w : 18,376
	x : 376
	y : 14,814
	z : 234
./count15-2-01.png (chart as image)

This is a simple bar chart for the present purposes. Future topics will cover how to make it look nicer.

Here is another typical form of XML data using nodes with nodes with text.

Here is the Python code [#3]

import matplotlib.pyplot as plt
import numpy as np
np.random.seed(0)
import xml.etree.ElementTree as et
xmlFs1 = "./letters2.xml"
print("XML data from \"{0:s}\" using nodes:".format(xmlFs1))
xml1 = et.parse(xmlFs1)
root1 = xml1.getroot()
# Echo and transform the JSON data
print("")
print("\tLetter : Count")
print("")
dataList1 = []
for record1 in root1:
	name1 = record1.find("name").text
	count1 = int(record1.find("value").text)
	dataList1.append([name1,count1])
	print("\t{0:s} : {1:,}".format(name1,count1))
# transform data into needed form
xData1 = []
yData1 = []
for name1,count1 in dataList1:
	xData1.append(name1)
	yData1.append(count1)
# set plot parameters
fontDict1 = {
	"family" : "Verdana",
	"weight" : "bold",
	"size" : 16
	}
plt.rc("font", **fontDict1)
# make the bar chart
rlen1 = 1
clen1 = 1
width1 = 1024
height1 = 360
dpi1 = 72
figsize1 = (width1/dpi1,height1/dpi1)
fig1,ax1 = plt.subplots(rlen1,clen1,figsize=figsize1,dpi=dpi1)
y_pos1 = np.arange(len(xData1))
plt.bar(y_pos1, yData1)
plt.xticks(y_pos1, xData1)
plt.ylabel("Count")
plt.xlabel("Letter")
plt.title("Count by Letter")
# save the bar chart
print("")
pngFs1 = "./count15-3-01.png"
print("{0:s} (chart as image)".format(pngFs1))
fig1.savefig(pngFs1,bbox_inches="tight")

Here is the output of the Python code.

XML data from "./letters2.xml" using nodes:
	Letter : Count
	a : 59,900
	b : 11,302
	c : 14,311
	d : 34,483
	e : 95,247
	f : 17,852
	g : 13,528
	h : 62,509
	i : 46,347
	j : 2,321
	k : 4,449
	l : 25,939
	m : 19,154
	n : 51,311
	o : 54,741
	p : 9,918
	q : 183
	r : 37,468
	s : 44,630
	t : 72,396
	u : 20,651
	v : 7,458
	w : 18,376
	x : 376
	y : 14,814
	z : 234
./count15-3-01.png (chart as image)

This is a simple bar chart for the present purposes. Future topics will cover how to make it look nicer.