Monat: März 2018

The Anatomy Of A Python Class

robert / / Daily Code, OOP 
class Customer:

    #global limit = -1000

    def __init__(self):
        #in a real app these values would be provided most likely by a database
        self.balance = 0
        self.limit = -1000
        self.security_check = True
        self.is_active = True

    def credit_limit(self, balance):
        #limit = -1000
        if balance < self.limit:
            return False
        else:
            return True

    def withdraw(self, amount):
        #act_balance = self.balance - amount
        self.balance -= amount
        if (self.credit_limit(self.balance) == True):
            return self.balance
        else:
            return ("Withdrawl not possible. You reached the credit limit.")

    def deposit(self, amount):
        self.balance += amount
        return self.balance



a = Customer()

b = Customer()

print(a.withdraw(500))                        #   - 500
print(a.deposit(100))                         #   - 400

print(b.withdraw(1500))                       #   Withdrawl not possible. You reached the credit limit.

Day 69: Make Good Looking Tables With PrettyTable (Module)

robert / / Daily Code, Modules

 

Scripts running in the shell are pretty cool. But sometime you want to display tables that have no real format.

 

The module PrettyTable generates some – well pretty – tables with just a couple of lines.

 

The script takes a dictionary with the sizes of all planets in the solar system.

 

It exports it in a PrettyTable in descending order.

 

# PrettyTable module
# Create handsome tables in your shell
from prettytable import PrettyTable

planets = {"Mercury" : "4879",
        "Venus" : "12104",
        "Earth" : "12756",
        "Mars" : "6779",
        "Jupiter" : " 142984",
        "Saturn" : "120536",
        "Uranus" : "50724",
        "Neptune" : "49244"
        }

# create the table with two colums
size_table = PrettyTable(["Planet", "Diameter (km)"])

# go over every planet in dict and add a row for each
for item in planets:
    size_table.add_row([item, planets[str(item)]])

# sort planets from big to small
size_table.sort = True

print(size_table)

The output looks like this:

 

 

Day 66: Being A Scribe – Read From And Write To Files

robert / / Basics, Daily Code 
# Read and write files

# open the file with 'write'-mode
test_file = open("files_test.txt", "r")


# full list of file modes
# "w" - write text file (overwrite possible)
# "r" - read text file
# 'x' - write text file (includes error is file exists)
# 'a' - append to end of file
# 'rb' - read binary files
# 'wb' - write binary
# 'w+b' - read and write binary file
# 'xb' - write binary file (includes error is file exists)
# 'ab' - append to end of binary file

# Read files
print(test_file.read())                     # This is a test - full text

# Read one line
print(test_file.readline())                  # This is a test - one line


# iterate over text files
for line in test_file:
    print(line)                              # This is a test - all lines

# readline() is not very well suited to iterate over big files

# close files - you should alway close a file after using it!!!
test_file.close()

# Write to files
texty = open("files_test.txt", 'w')
texty.write("11 This is a test\n")
print(texty.read())
texty.close()

Day 64: Check If A String is a Palindrome With Python

robert / / Uncategorized

 

We get a string and check if it is a palindrome:

 

# Find out if a word is a palindrome
def palin(word):
    ''' take word, build inverted string
    and check if it is a palindrome '''

    word = word.replace(".", "")    # get rid of eventual "."
    word = word.lower()             # make lowercase

    length = len(word)
    new = list("")                  # build an empty list for the inversed string
    index = -1                      # -1 so we start building in reverse order

    # take every letter and add it to new list in reverse order
    for i in word:
        new.insert(index, i)
        index -= 1

    # change list to string
    new_str = "".join(new)

    # get rid of any spaces in a sentence
    word_stripped = word.replace(" ", "")
    new_stripped = new_str.replace(" ", "")

    # check if word and the reverse string are the same
    if (word_stripped == new_stripped):
        return (word + ": This is a palindrome")
    else:
        return (word + ": This is NOT a palindrome")

print(palin("Anna"))                    # anna: This is a palindrome

print(palin("peter"))                   # peter: This is NOT a palindrome

print(palin("Name not one man."))       # name not one man: This is a palindrome

Day 63: Indexing And Slicing

robert / / Basics, Daily Code 
# Indexing
# note: sets can't be indexed

my_guitars = ["Gibson Les Paul", "Ibanez RG", "Fender Stratocaster"]

print(my_guitars[0])                # Gibson Les Paul

# Python allows negative indexing. -1 returns the last item aso
print(my_guitars[-1])               # Fender Stratocaster
print(my_guitars[-2])               # Ibanez RG


# indexing a tuple
print(("Marshall", "Laney", "Orange")[1])       # Laney

# indexing a string
print("Wampler"[3])                 # p - index starts at 0

# slicing
print(my_guitars[0:2])              # ['Gibson Les Paul', 'Ibanez RG']


# note: the first index is optional. negative indexing works here as well
print(my_guitars[:2])              # ['Gibson Les Paul', 'Ibanez RG']
print(my_guitars[:-1])              # ['Gibson Les Paul', 'Ibanez RG']


#Examples

# get first and last letter
name = "Robert"

print(name[0])                      # R
print(name[-1])                     # t

# delete the file extension
filename = "document.txt"

print(filename[0:-4])               # document

Day 61: Functions Overview

robert / / Basics, Daily Code 
# Functions

# declaring a Function
# if there is no return in the Functions
# python will return the last command line

def func(para1, para2):
    ''' explain what happens here '''
    sum  = para1 + para2                # variables declared inside functions are local
    return sum

#calling a function
sum = func(13,5)               # 18 this sum is not related to the sum-variable in the function
print(sum)


#using default parameters
def def_func(x, y=3):          # y=3 is a default parameter
    return x + y

print(def_func(2))             # 5 - the function will use the default parameter

print(def_func(5,8))           # 13 - default parameters can be overwritten


# Examples:

def is_odd(num):
    ''' returns true if number is odd '''
    if (num % 2 == 0):
        return True
    else:
        return False

print(is_odd(4))                                    # True


def is_prime(x):
    ''' checks if number is prime '''
    ''' only natural number bigger 1 can be considered primes '''
    if (x > 1):
        return all(x % i for i in range(2, x))
    else:
        return False                                # if number is 1 or less

print(is_prime(3))                                  # True