Basic python code examples

basic_bottle_template.py

+from bottle import Bottle, request, run
+
+app = Bottle()
+
+
+@app.route('/say_hello', method='POST')
+def hello():
+    name = request.forms['name']
+    return "Hello {}!".format(name)
+
+run(app, host='localhost', port=8080)

conditionals.py

+list = ['Bob', 'Sue', 'Sally', 'George', 'Karen', 'Mike', 'Carol', 'Matt']
+
+for name in list:
+    if name is 'Bob':
+        print 'I found Bob'
+    elif name is 'Sally' or name is 'Matt':
+        print 'The managers are here.'
+    elif name is 'Sue' and 'George' in list:
+        print "Uhoh... We can't seat them together"
+    else:
+        print "{} has arrived".format(name)

dicts.py

+Bob = {'Hair': 'Pink', 'Age': 33, 'Height': '6\'1"'}
+print Bob['Hair']
+print Bob['Age'] * 2
+
+# Print only the keys in the dict
+for key in Bob.keys():
+    print key
+
+# Print only the values in the dict
+for value in Bob.values():
+    print value
+
+# Print each pair using the "unpacking" syntax
+for key, value in Bob.items():
+    print "Bob's {}: {}".format(key, value)
+
+# Dicts create more explicit string templates
+template = "Bob is a great guy. He has {Hair} hair, is {Age} years old, and {Height} tall."
+print template.format(**Bob)
+
+
+# Keys can be reassigned
+Bob['Hair'] = 'Brown'

files.py

+with open('/tmp/myfile.txt', 'w') as output_file:
+    output_file.write('Hello World')
+
+with open('/tmp/myfile.txt', 'r') as input_file:
+    for line in input_file:
+        if line.startswith('Hello'):
+            print line
+
+with open('/tmp/myfile.txt', 'r') as input_file:
+    content = input_file.read()
+    print content
+
+######################################################
+# File modes
+# r = read
+# w = write
+# r+ = read and write
+# b = binary mode
+# r+b = read and write in binary mode
+######################################################

functions.py

+# Create and execute a funtion that accepts no inputs
+def greet_the_world():
+    print "Hello world!"
+
+greet_the_world()
+
+
+# Functions can return values
+def get_greeting():
+    return "Hello world!"
+
+greeting = get_greeting()
+print greeting
+
+
+# Functions can require inputs
+def greet_someone(who):
+    print "Hello {}!".format(who)
+
+greet_someone('Bob')
+
+
+# or inputs can be made optional by specifying default values
+def greet_someone(who='coder'):
+    print "Hello {}!".format(who)
+
+greet_someone()

imports.py

+# You can import an entire library
+import bottle
+bottle.run()
+
+# or just the parts you need:
+from bottle import run, route
+run()

lists.py

+list = ['Bob', 'Sue', 'Sally', 'George', 'Karen', 'Mike', 'Carol', 'Matt']
+
+# get an item from the list:
+print list[2]
+
+# get the last item in a list:
+print list[-1]
+
+# get a chunk of the list:
+print list[2:5]
+
+# cherry pick every second item in the list:
+print list[:2:]
+
+# Reverse the list
+print list[::-1]
+
+# Assignment
+list[1] = 'Terry'
+
+# Strings as lists
+mac = "The customer's mac address is 9B:B9:9D:48:47:D4"
+print mac[-17]
+print mac[-17:]
+
+################################################################
+# You can't change strings by assigning new characters to slices
+# Instead, create the pieces and add them together
+################################################################

loops.py

+list = ['Bob', 'Sue', 'Sally', 'George', 'Karen', 'Mike', 'Carol', 'Matt']
+
+# Print each item in the list
+for item in list:
+    print item
+
+# Print the last 3 items in the list
+for item in list[-3]:
+    print item
+
+# Print the 3rd from last character of each item in the list
+for item in list:
+    print item[-3]
+
+# Check each item in the list, print everything but "Bob"
+for item in list:
+    if item is not "Bob":
+        print item
+
+# While loops are the same syntax
+# "Iterator loops" like this one should generally be replaced
+# with "for i in range(0, 10):" style for loops
+x = 0
+while x is not 10:
+    print "X too small: {}".format(x)
+    x += 1
+
+
+# List Comprehensions are an alternate, but more compact syntax for
+# "simple loops" that create lists
+upper_list = []
+for name in list:
+    upper_list.append(name.upper())
+
+
+upper_list = [name.upper() for name in list]
+print upper_list

networking.py

+# Bring in the requests library
+import requests
+
+# Send a 'GET' type request and print the response
+r = requests.get('https://www.google.com')
+print r.text
+
+# Send data to a url
+url = 'https://www.google.com'
+payload = {'name': 'Bob', 'Hair': 'Pink'}
+r = requests.post(url, data=payload)

operators.py

+# Assignment
+a = 1
+b = 2
+c = 5
+
+# Arithmetic
+print a + b    # 3
+print a - b    # -1
+print a * b    # 2
+print a / b    # 0.5
+
+#######################################
+# If it divides evenly, return 0; otherwise, returns the remainder
+print a % b    # 1
+#######################################
+
+print a ** b   # 1
+print a // b   # 0
+
+# Comparison
+print a == b    # False
+print a != b    # True
+print a > b     # False
+print a < b     # True
+print a >= b    # False
+print a <= b    # True
+
+# Compound Assignment
+c += a
+print c    # c = 6
+
+c -= a
+print c    # c = 5
+
+# Operators on strings
+# Assignment
+a = 'aabb'
+b = 'bbcc'
+
+# Arithmetic
+print a + b    # 'aabbbbcc'
+print a * 2    # 'aabbaabb'
+
+# Comparison
+print a == b    # False
+print a != b    # True
+
+# Compare Alphabetically
+print a > b     # False
+print a < b     # True
+print a >= b    # False
+print a <= b    # True

strings.py

+# Single and double quotes are interchangable
+quote = 'he exclaimed "I am Sir Didymus, and none may pass without my permission."'
+print quote
+
+# String formatting allows you to create templates to be filled in later
+template = "%s wrote this code in %s"
+output = template.format("Bob", "Python")
+print output
+
+
+output = "{} wrote this code in {}".format("Bob", "Python")
+print output
+
+# Triple quoted strings (Heredocs in other languages) allow multi-line strings
+text_block = '''
+Sometimes you want to include Python code in a string without
+\e\s\c\a\p\i\n\g everything:
+
+for item in list:
+    do_stuff_with(item)
+
+"Triple quoted strings" (Heredocs in other languages) let you
+do just that.'''
+print text_block