Kategorie: Daily Code

# dictionaries
import collections
# creating a dictionary
data = {"first" : "Linus", "last" : "of Paros"}

# add keys and values
data["age"] = 3
data["job"] = "Dog"

print(data)                     # {'first': 'Linus', 'last': 'of Paros', 'age': 3, 'job': 'Dog'}

#retrieving values
print(data["first"])            # Linus

print(data["first"] + " " + data["last"] + " is a " + data["job"] ) # Linus of Paros is a Dog

# check if a key is in the dict with in operator
print("first" in data)          # True
print("car" in data)            # False

# with get you can set a default in case a key is not found in a dict
shortcut = data.get("address", "unknown")

print(shortcut)                 # unknown

# remove keys and values
numbers = {"1" : "true", "2" : "false","2" : "false", "3" : "true"}

del numbers["2"]

print(numbers)                  # {'1': 'true', '3': 'true'}

# iterating over dictionaries
age = {"Don" : 55, "Cindy" : 52, "James" : 42, "Sara" : 35}

for name in age:
    print(name)                 # Don, Cindy, James, Sara

for name in age.values():
    print(name)                 # 55, 52, 42, 35

# Iteration examples

# get the average length of items in the list
list = ["Sara", "Christiano", "Dorothy", "Pete", "Peter"]
list.append("Robert")
average = 0

for name in list:
    average += len(name)                 # adds the length of every item to average

average_length = average / len(list)
print("The average length is: " + str(average_length))      #   ...length is: 6.0

# find an item in list
if "Sara" in list:
    print("found Sara")                 # found Sara
else:
    print("Not found")

if "Tucker" in list:
    print("found Tucker")
else:
    print("Not found")                  # Not found

# iterating with while loops

n = 10
numb = []
while n > 0:
    numb.append(n)
    n -= 1

print(numb)                     # [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

# list - holds a list of objects
# can be of any type and mix them
# lists are mutable

names = []                      # create an empty list
names_1 = ["Harvey", "Charles"] # create a populated list

# with list a string will return as individual chars
custom_list = list("Robert")

print(custom_list)              # ['R', 'o', 'b', 'e', 'r', 't']

# get specific items with index (index starts at 0)
print(names_1[0])               # Harvey
print(names_1[1])               # Charles

#list insertion

#insert an item with index
names_1.insert(1, "Dave")
print(names_1)                  # ['Harvey', 'Dave', 'Charles']

#append an item at the end of the list
names_1.append("Clara")
print(names_1)                  # ['Harvey', 'Dave', 'Charles', 'Clara']

#replace an item with index
names_1[1] = "Sophie"
print(names_1)                  # ['Harvey', 'Sophie', 'Charles', 'Clara']

# delete an list item
#1
names_1.remove("Harvey")
print(names_1)                  # ['Sophie', 'Charles', 'Clara']

#2
del names_1[2]
print(names_1)                  # ['Sophie', 'Charles']

# sorting a list

# sort strings alphabetically
names_1.sort()
print(names_1)                  # ['Charles', 'Sophie']

# sort numbers
numbers = [3,2,7,-3,99]
print(numbers)                  # [3, 2, 7, -3, 99]

numbers.sort()
print(numbers)                  # [-3, 2, 3, 7, 99]

# ATTENTION: You can't sort numbers and strings in one list -> error

#example

# tuples - holds unmutable items
# tuples can't be changed
# tuples can serve as keys in dictionaries
# ideal for unchanging values like pi or 24 hours

# crate a tuple
tuple_name = ("Steven", "Alice", "Vincent")

print (tuple_name)

print(tuple_name[1])                # Alice

# cannot append to tuples

# Sets
# sets are mutable and don't care about order
# they are great to check membership, remove duplicates and are hashable

digits = [0,1,1,2,3,4,4,5,6,7,8.5,9]

digit_set =  set(digits)        # removes duplicates

print(digit_set)                # Output: {0, 1, 2, 3, 4, 5, 6, 7, 8.5, 9}

print(9 in digit_set)           # True - checks if 9 is a member of the sets

# you can add or remove other Sets
even = {2,4,6,8,10}                # note we are using {} here instead of []

odd = digit_set - even              # remove even from digit_set

print(odd)                          # Output {0, 1, 3, 5, 7, 8.5, 9}

 

I am back – it’s been a week. It was an unplanned break since my son got a fever and than I got an unexpected job offer.

 

I own a very beautiful Gibson Les Paul guitar that I love very much. But the action – the distance between fret and string – is a bit too far off.

 

That is no problem because the Gibson website tells me exactly that the correct distance should be 3/64 inches! Ok. What?

 

First of all I am European. Inches are not unheard of and I know that one inch are 25.4 millimetres. But 3/64 inches? Come on!

 

Thank god for Python:

 

inches = "3/64"                                 # the inch value

slash_pos = inches.find("/") + 1                # look where the slash seperates the numbers

first_num = inches[0]                           # get the numerator
sec_num = inches[slash_pos:]                    # get the denominator

dec_inch = 1 / int(sec_num) * int(first_num)    # create a decimal inch value

get_mm = 25.4 * dec_inch                        # convert it to mm

print(inches + " inches are ""%.2f" % get_mm + " mm")  # round the float to to decimals


# Output: 3/64 inches are 1.19 mm

 

# Conditionals in Python:
# <         less than 
# >         greater than 
# <=        equal or less 
# >=        equal or greater
# ==        equal to
# !=        not equal to
# is        identical object
# is not    Not identical object


number = input("Enter a number: ")

if (int(number)%2 == 0):
    print("Number is even")
else:
    print("Number is odd")

# the conditionals 'is' and 'is not'
name_1 = "matt"
name_2 = "tim"
name_3 = name_1

if (name_1 is name_3):                  # statement is true
    print("The same object!")

if (name_1 is not name_2):              # this statement is also true
    print("Two different objects!")

score = 78

if (score > 90):
    grade = "A"
elif (score > 80):
    grade = "B"
elif (score > 70):
    grade = "C"
else:
    grade = "Failed"

print(grade)                        # C

# combining conditionals
name = "Duff"
gunsnroses = False

if (name == "axl" or
    name == "slash" or
    name == "Duff" or
    name == "steven" or
    name == "izzy"):
    gunsnroses = True
    print(gunsnroses)                           # true
else:
    gunsnroses = False
    print(gunsnroses)

# a more efficent way to do the above
gunner = False
gnr = {"Axl", "Duff", "Steven", "Izzy", "Slash"}
gunner = name in gnr

print(gunner)                                   # true

 

 

 

 

One of my most dreaded tasks on the computer is the renaming of images. When I import them from the digicam they’re usually just numbered.

 

I like to name my photos with a concrete name. For example „rome_2015“ or „linus“ when I have taken images of my dog. The images also get a numbered index 01,02,03,aso.

 

Well it’s dreaded not anymore because I wrote a little Python script that will do all the tedious work for me in an instance.

 

Not only do we rename the images, the program will also detect other files (like system files) and leave them untouched.

 

Here is a before and after:

 

 

To do this the python script needs to know the directory where the photos are located, the desired filename and what file type we like to change (.jpg)

 

Here is the code (the comments explain the function line by line)

 

import os

directory = "img/"                              # get the image-directory
absolute_dir = os.getcwd()                      # get your current working dir
complete_dir = absolute_dir + "/" + directory   # built a complete path to the images

#if you would need the desktop dir on mac - use the line below
#complete_dir = os.path.expanduser("~/Desktop/test/")

num_of_files = 0                                # set counter for image-numbers
name = "linus"                                # what you want to name you images

# go through every file in given dir
for filename in os.listdir(complete_dir):
    if filename.endswith(".jpg"):               # only operate on .jpg files, can be changed to any filetype
        num_of_files += 1                       # thats the number we indes our fotos with

        new_name = name + "_" + str(num_of_files) + ".jpg" # build the new file name

        # rename the file, we need complete_dir here because
        # listdir and rename work on different (absolute and increment) directorys
        # otherwise we will get an error
        os.rename(complete_dir + filename, complete_dir + new_name)

 

Just something quick today I stumbled upon yesterday:

 

# checking if the variable name has a value
# using the most efficient way

name = input("Enter your name: ")


# this works, but dont do this
if (len(name) > 0):
    print("true")
else:
    print("false")

# this works also, but it's also bad style
if (name != ""):
    print("true")
else:
    print("false")

# This is the proper Python way
# if name has a value it checks out true automatically
if (name):
    print("true")
else:
    print("false")