Category: Python

import re
re.findall(needle,haystack)

def t_LANGLESLASH(token):
    r'
def t_NUMBER(token):
	r"[0-9]+"
	token.value = int(token.value)
	return token

def t_STRING(token):
    r'"[^"]*"'
    return token

def t_WORD(token):
    r'[^ <>]+'
    return token

def t_IDENTIFIER(token):
    r'[a-zA-Z][a-zA-Z_]*'
    return token

def t_NUMBER(token):
    r'-?[0-9]+(:?\.[0-9]*)'   
    return token

	

edges = {(1,'a'):2,
	(2, 'a'): 2,
	(2, '1'): 3,
	(3, '1'): 3}
	accepting = [ 3 ]

	def fsmsim(string, current, edges, accepting):
		if string == ""
			return current in accepting
		else:
			letter = string[0]
			if (current, letter) in edges:
				destination = edges[(current,letter)]
				remaining_string = string[1:]
				return fsmsim(remaining_string,destination,edges,accepting)
			else:
				return False
	print fsmsim("aaa111",1,edges,accepting)

import re

def umnums(sentence):
	r = r"[0-9]+"
	sum = 0
	for found in re.findall(r,sentence):
		sum = sum + int(found)
	return sum

(?:[a-z]+-[a-z]+)|(?:[a-z]+)

def nfsmsim(string, current edges, accepting):
	if string == "":
		return current in accepting
	else:
		letter = string[0:1]
		if (current, letter) in edges:
			remainder = string[1:]
			newstates = edges[(current, letter)]
			for newstate in newstates:
				if nfsmsim(remainder, newstate, edges, accepting):
					return True

	if current in visited:
		return None
	elif current in accepting:
		return ""
	else:
		newvisited = visited + [current]
		for edge in edges:
			if edge[0] == curent:
				for newstate in edges[edge]:
					foo = nfsmaccepts(nestate, edges, accepting, newvisited)
					if foo != None:
						return edge[1] + foo
		return None

Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:19:22) [MSC v.1500 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> "Ada Lovelace".find(" ")
3
>>> "Alan Turing".find("n",4)
9

def myfirst_yoursecond(p,q):
	pindex = p.find(" ")
	qindex = q.find(" ")
	return p[ :pindex] == q[qindex+1:]

>>> "Python is fun".split()
['Python', 'is', 'fun']
>>> "July-August 1842".split()
['July-August', '1842']
>>> "6*9==42".split()
['6*9==42']

Regular expression [1-3][4-8][a-b]

>>> r"[0-9][0-9]"
>>> re.findall(r"[0-9][0-9]", "July 28, 1821")
>>> re.findall(r"[0-9][0-9]", "12345")

r”a+”, r”[0-1]+”
regular expression rule is maximum match eat single match
re.findall(r”[0-9][ ][0-9]+”, “a1 2b cc3 44d”)
r”[0-9]+%”
r”[a-z]+|[0-9]+”,”Goothe 1798″

regexp = r”[a-z]+-?[a-z]+”

>>> re.findall(r”[0-9].[0-9]”, “1a1 222 cc3”)
[‘1a1’, ‘222’]

edges = {(1,'a'):2,
	(2, 'a'): 2,
	(2, '1'): 3,
	(3, '1'): 3}

In Python, the map concept appears as a built-in data type called a dictionary. A dictionary contains key-value pairs. Dictionaries is extremely easy to use and useful. Here’s a sample of setting up a dictionary.

locations = {'North America': {'USA': ['Mountain View']}}
locations['North America']['USA'].append('Atranta')
locations['Asia'] = {'India': ['Bangalore']}
locations['Asia']['China'].append = ['Shanghai']
locations['Africa'] = {'Egypt': ['Cairo']}

usa_sorted = sorted(locations['North America']['USA'])
for city in usa_sorted
    print city

asia_cities = []
for countries, cities in location['Asia'].iteritems():
    city_country = cities[0] + " - " + countries
    asia_cities.append(city_country)
asia_sorted = sorted(asia_cities)
for city in asia_sorted:
    print city

When hash table collision, bucket store data.

Hash Value = (ASCII Value of First Letter * 100) + ASCII Value of Second Letter

hash table

class HashTable(object):
    def __init__(self):
        self.table = [None]*10000

    def store(self, string):
        hv = self.calculate_hash_value(string)
        if hv != -1:
            if self.table[hv] != None:
                self.table[hv].append(string)
            else
                self.table[hv] = [string]

    def lookup(self, string):
        hv = slef.calculate_hash_value(string)
        if hv != -1:
            if self.table[hv] != None:
                if string in self.table[hv]:
                    return hv
        return -1

    def calculate_hash_value(self, string):
        value = ord(string[0])* 100 + ord(string[1])
        return -1

Tree DFS, In-order

class Queue:
    def __init__(self, head=None):
        self.storage = [head]

    def enqueue(self, new_element):
        self.storage.append(new_element)

    def peek(self):
        return self.storage[0]

    def dequeue(self):
        return self.storage.pop(0)

def delete_first(self):
    deleted = self.head
    if self.head:
        self.head = self.head.next
        deleted.next = None
    return deleted

class Element(object):
    def __init__(self, value):
        self.value = value
        self.next = None
        
class LinkedList(object):
    def __init__(self, head=None):
        self.head = head
        
    def append(self, new_element):
        current = self.head
        if self.head:
            while current.next:
                current = current.next
            current.next = new_element
        else:
            self.head = new_element

    def insert_first(self, new_element):
        new_element.next = self.head
        self.head = new_element

    def delete_first(self):
        if self.head:
            deleted_element = self.head
            temp = deleted_element.next
            self.head = temp
            return deleted_element
        else:
            return None

class Stack(object):
    def __init__(self,top=None):
        self.ll = LinkedList(top)

    def push(self, new_element):
        self.ll.insert_first(new_element)

    def pop(self):
        return self.ll.delete_first()

This class to represent how classy someone
or something is.”Classy” is interchangable with “fancy”.
If you add fancy-looking items, you will increase
your “classiness”.

class Classy(object):
    def __init__(self):
        self.items = []

    def addItem(self, item):
    	self.items.append(item)
 
    def getclassiness(self):
    	classiness = 0
    	if len(self.items) > 0:
    		for item in self.items:
        		if item == "tophat":
    				classiness += 2
    			elif item == "bowtie":
    				classiness += 4
    			elif item == "monocle":
    				classiness += 5
    		return classiness

notation: expression
():parenthesis

“””input manatees: a list of “manatees”, where one manatee is represented by a dictionary
a single manatee has properties like “name”, “age”, et cetera
n = the number of elements in “manatees”
m = the number of properties per “manatee” (i.e. the number of keys in a manatee dictionary)”””

def example1(manatees):
for manatee in manatees:
print manatee[‘name’]

def example2(manatees):
print manatees[0][‘name’]
print manatees[0][‘age’]

def example3(manatees):
for manatee in manatees:
for manatee_property in manatee:
print manatee_property, “: “, manatee[manatee_property]

def example4(manatees):
oldest_manatee = “No manatees here!”
for manatee1 in manatees:
for manatee2 in manatees:
if manatee1[‘age’] < manatee2['age']: oldest_manatee = manatee2['name'] else: oldest_manatee = manatee1['name'] print oldest_manatee

class Element(object):
    def __init__(self, value):
        self.value = value
        self.next = None
        
class LinkedList(object):
    def __init__(self, head=None):
        self.head = head
        
    def append(self, new_element):
        current = self.head
        if self.head:
            while current.next:
                current = current.next
            current.next = new_element
        else:
            self.head = new_element
            
    def get_position(self, position):
        counter = 1
        current = self.head
        if position < 1:
            return None
        while current and counter <= position:
            if counter == position:
                return current
            current = current.next
            counter += 1
        return None
    
    def insert(self, new_element, position):
        counter = 1
        current = self.head
        if position > 1:
            while current and counter < position:
                if counter == position -1:
                    new_element.next = current.next
                    current.next = new_element
                current = current.next
                counter += 1
        elif position == 1:
            new_element.next = self.head
            self.head = new_element
    
    def delete(self, value):
        current = self.head
        previous = None
        while current.value != value and current.next:
            previous = current
            current = current.next
        if current.value == value:
            if previous:
                previous.next = current.next
            else:
                self.head = current.next

#THIS IS A WEBSERVER FOR DEMONSTRATING THE TYPES OF RESPONSES WE SEE FROM AN API ENDPOINT
from flask import Flask
app = Flask(__name__)

#GET REQUEST

@app.route('/readHello')
def getRequestHello():
	return "Hi, I got your GET Request!"

#POST REQUEST
@app.route('/createHello', methods = ['POST'])
def postRequestHello():
	return "I see you sent a POST message :-)"
#UPDATE REQUEST
@app.route('/updateHello', methods = ['PUT'])
def updateRequestHello():
	return "Sending Hello on an PUT request!"

#DELETE REQUEST
@app.route('/deleteHello', methods = ['DELETE'])
def deleteRequestHello():
	return "Deleting your hard drive.....haha just kidding! I received a DELETE request!"

if __name__ == '__main__':
    app.debug = True
    app.run(host='0.0.0.0', port=5000)