Python

Question 1

Syntax: open a file for reading [#to write in it]

Answer 1

f = open(“foo.txt”, “r”) # f = open(“bar.txt”, “w”)

Question 2

Syntax: read a file

Answer 2

data = f.read #where f is the result of: open(“foo.txt”, “r”)

Question 3

Syntax: write to a file

Answer 3

g.write(“some text\n”) #where g is a result of open(“bar.txt”, “w”)

Question 4

Syntax: reading a file one line at a time

Answer 4

f = open(“foo.txt”,”r”)
for line in f:
#process line
f.close()

Question 5

Syntax: reading from the web

Answer 5

import urllib

u = urllib.urlopen("www.google.com")
data = u.read()

Question 6

Syntax: parse an xml doc

Answer 6

from xml.etree.ElementTree import parse

doc = parse(‘rt22.xml’)

Question 7

Syntax: iterate over an element in a parsed xml doc

Answer 7

for element in doc.findall('element'):
    #code

Question 8

Syntax: extract data from a parsed xml doc

Answer 8

d = element.findtext(‘d’)

Question 9

Syntax: show a page in a browser

Answer 9

import webbrowser

webbrowser.open(‘http://…’)

Question 10

Syntax: chained comparison

Answer 10

if x < y >= z:
#same as: if x < y and y >= z: 
#but! y only evaluated once, z not if x <y false

Question 11

Syntax: preferred way to open a file! (to ensure it is closed)

Answer 11

with open('name', 'mode') as f:
    read_data = f.read()

Question 12

Syntax: start the development server

Answer 12

python manage.py runserver

Question 13

Syntax: awesome list comprehension

Answer 13

output = ‘, ‘.join([p.question for p in latest_poll_list])