I took a class back in November, 2017 on introductory python @ Fab Lab KUET This is a summary of the things I covered. https://github.com/zabir-nabil/fab-lab-python-intro-workshop (in case you want to visit the github repo I created for the workshop!)

print("Hi there, Python 3")     # How to print something?

Hi there, Python 3

semicolon

Where are those semicolons?

print('Hi '); print('there, '); print('Pyhton 3')    # Interpreters vs Compilers
                                                     # Youtube streaming vs Downloading analogy

Hi 
there, 
Pyhton 3

a = input('a = ')                             # CLI
b = input('b = ')

a += '0'                                      # string concatenation
b += '0'                                      # operator overloading

print(type(a))                                # string

print(a+b)
                            

a = 16
b = 2
<class 'str'>
16020

a = input('a = ')                             # CLI
b = input('b = ')

a += '0'                                      # string concatenation
b += '0'

print(type(a))                                # string

print(a+b)

a = int(a)                                    # type-casting
b = int(b)

print(type(b))                                # integer

a += 5
b += 5

print(a,b,a+b)

a = 10
b = 5
<class 'str'>
10050
<class 'int'>
105 55 160

a = input('a = ')                             # CLI
b = input('b = ')

a += '0'                                      # string concatenation
b += '0'

print(type(a))                                # string

print(a+b)

a = int(a)                                    # type-casting
b = int(b)

print(type(b))                                # integer

a += 5
b += 5

print(a,b,a+b)

if a < b:
    print('Just gonna print a 0')
elif a == b:
    print('Just gonna print a 1')
else:
    print("Can't predict :( ")

print(a//b)                                   

a = 7
b = 17
<class 'str'>
70170
<class 'int'>
75 175 250
Just gonna print a 0
0

a little bit of modular arithmetic

• How many multiples of $3$ are there in a list?

• Find all such $y$ such that, $y = 57x + 13$ where, $0 <= y <= 1000$ and $x$ belongs to *$N$

# a_list = [1,2,3,4,5,6,7,8,9,10]          # list

a_list = list(range(1,11))               # why 11?

print(type(a_list))

print(a_list)

for a_i in a_list:
     if a_i % 3 == 0:
        print(a_i,end = ' ')

<class 'list'>
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
3 6 9 

y_rng = range(1,1001)                    # why 1001?

print(type(y_rng))

for y in y_rng:
    if y % 57 == 13:
        print(y,end=' ')

<class 'range'>
13 70 127 184 241 298 355 412 469 526 583 640 697 754 811 868 925 982 

! pip install future             # Using pip

Requirement already satisfied: future in c:\anaconda3\lib\site-packages

packages, subpackages and modules

Requirement already satisfied: future in ‘dir’ ….

• Let’s see, how the directory ‘dir’ is organized
• __init__.py, packages, subpackages, modules, namespace, __path__

from future.backports import datetime as dt
 
# year = input('year : ')

print(dt)

print(dir(dt),'\n')                 #  dir() method tries to return a list of valid attributes of the object

today = dt.date.today()

print(today,'\n')

another_day = dt.date(2017,11,11)

print(another_day)

<module 'future.backports.datetime' from 'C:\\Anaconda3\\lib\\site-packages\\future\\backports\\datetime.py'>
['MAXYEAR', 'MINYEAR', 'PY2', '_EPOCH', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'absolute_import', 'bytes', 'date', 'datetime', 'datetime_CAPI', 'division', 'int', 'map', 'native_str', 'object', 'print_function', 'round', 'str', 'time', 'timedelta', 'timezone', 'tzinfo', 'unicode_literals'] 

2017-11-04 

2017-11-11

python 2/3 compatibility and future

• run python 2 code from python 3 using past

from past.builtins import xrange                # running python 2 in python 3

a = list(xrange(11))

a[0] += 2
a[0] **= 2

print('length of a = ',len(a),'\n')

a[len(a)-1] *= 2 

print(sorted(a))

print('\n')

for x in xrange(11):
    print(a[x],end = ' ')
    
print('\n')
    
a.sort()

for x in xrange(11):
    print(a[x],end = ' ')

length of a =  11 

[1, 2, 3, 4, 4, 5, 6, 7, 8, 9, 20]


4 1 2 3 4 5 6 7 8 9 20 

1 2 3 4 4 5 6 7 8 9 20 

from __future__ import division            # running python 3 in pyhton 2

our own functions and default parameters

• def, return

def my_fun():
    
    print("Hi there, Python 3")

my_fun()

Hi there, Python 3

def your_fun(a,b,c=5):
    
    print(a,b,c)
    return a * b + c

k1 = your_fun(5,4,3)
print(k1)
k2 = your_fun(1,2)
print(k2)

5 4 3
23
1 2 5
7

def add_str(a, c, i_am_string=''):          # why i_am_string is the last argument?
    i_am_string += a
    i_am_string += c
    return i_am_string

st = add_str('a','b')
print(st)
st = add_str('c','d')
print(st)

ab
cd

let’s develop our lil_geometry module

• go to a new fresh directory
• create a folder 'pack_lev1'
• inside, 'pack_lev1' create a python script named 'lil_geometry.py'

# lil_geometry.py
import math as m

def area_of_circle(rad):
    return 2*m.pi*rad


print(__name__)

__main__

# lil_geometry.py
import math as m

def area_of_circle(rad):
    return 2*m.pi*rad


print(__name__)

if ( __name__ == '__main__' ):
    rad = input('Enter radius : ')
    print("radius of cirlce is {}".format(area_of_circle(int(rad))))

__main__
Enter radius : 12
radius of cirlce is 75.39822368615503

module_test

• go to root
• create a script named 'module_test'

# testing module lil_geometry.py

from pack_lev1 import lil_geometry as lg

running module_test

• open cmd in that folder and type 'python module_test.py'

# testing module lil_geometry.py

from pack_lev1 import lil_geometry as lg

print('module_test __name__ : {}'.format(__name__))

print(lg.area_of_circle(5))  # using functions from imported module

github, git

• a break for me ` ` :P
• go to https://github.com and open an account
• verify email address

pip, easy_install and setup.py

• https://github.com/pyjokes/pyjokes
• clone this repo
• python setup.py install command

! cd

% pwd

'A:\\GitUps\\FabLabIntroPythonWorkshop\\fab-lab-python-intro-workshop\\Notebook'

• Go to the folder where you cloned pyjokes
• Shift + Right Mouse button -> Open CMD here

In cmd, type

• python
• import pyjokes as pj
• a_joke = pj.get_joke()
• print(a_joke)

forget about pycharm for a moment

• Go to a new fresh directory
• Create a new python script 'finally.py'
• Write some creative piece of code using just an editor
• Open cmd in that folder
• python finally.py

command line arguments

• sys
• argv
• argv[0] is name of the script

import sys as s_

print(s_.argv)

if len(s_.argv) == 1:
    print('The name of the script is {} and there are no extra args'.format(argv[0]))
elif len(s_.argv) == 3:
    print('First name : {} Last name : {}'.format(s_.argv[1],s_.argv[2]))
    

import sys as s_

print(s_.argv)

if len(s_.argv) == 1:
    print('The name of the script is {} and there are no extra args'.format(argv[0]))
elif len(s_.argv) == 3:
    print('First name : {1} Last name : {0}'.format(s_.argv[1],s_.argv[2]))
    

['C:\\Anaconda3\\lib\\site-packages\\ipykernel_launcher.py', '-f', 'C:\\Users\\zabir\\AppData\\Roaming\\jupyter\\runtime\\kernel-ffc5e574-b2b9-480f-b1ea-0b1b87f3d267.json']
First name : C:\Users\zabir\AppData\Roaming\jupyter\runtime\kernel-ffc5e574-b2b9-480f-b1ea-0b1b87f3d267.json Last name : -f

---

Existence is pain!