Please enable JavaScript.

Coggle requires JavaScript to display documents.

Python (Generators (A simple way to create iterators that provide a stream…

Python

3rd party lib imports

# that executes the file and runs the code within it
import 3rd_party_file_without_py as fn
fn.my_function(1234)

3rd_party_file_without_py.py:

def my_function(param):
    return param

def main():
    print("Testing my_function")
    assert(my_function(3) == 3)

    print("All tests passed")


if __name__ == "__main__":
    # is only called when the file is executed while not being imported
    main()

requirements.txt

beautifulsoup4==4.5.1
bs4==0.0.1
pytz==2016.7
requests==2.11.1

- - - - The lower index bound is inclusive
        The opper index bound is exclusive
  - - - capitalized_cities = [city.title() for city in cities]
    - - squares = [x**2 for x in range(9) if x % 2 == 0]
    - - squares = [x**2 if x % 2 == 0 else x + 3 for x in range(9)]
      - As this doesn't work
        
        squares = [x**2 for x in range(9) if x % 2 == 0 else x + 3]

Loops

Range

For Loop

for number in range(4):
    print(number)

cities = ['new york city', 'mountain view', chicago', 'los angeles']

for index in range(len(cities)):
    // .title() capitalizes a string
   cities[index] = cities[index].title()

for key, value in cast.items():
    print("Actor: {}    Role: {}".format(key, value))

cast = {
       "Julia Louis-Dreyfus": "Elaine Benes",
        "Jason Alexander": "George Costanza",
        "Michael Richards": "Cosmo Kramer"
        }

for word in book_title:
    word_counter[word] = word_counter.get(word, 0) + 1

While loop

while break_num < end_num:
    break_num += count_by

Functions

def cylinder_volume(height, radius=5):
    pi = 3.14159
    return height * pi * radius ** 2

cylinder_volume(20) # by position
cylinder_volume(20, 6) # by position
cylinder_volume(radius=7, height=10) # by name

Docstrings (JavaDoc)

def population_density(population, land_area):
    """Calculate the population density of an area. 

    INPUT:
    population: int. The population of that area
    land_area: int or float. This function is unit-agnostic, if you pass in values in terms     of square km or square miles the function will return a density in those units.

    OUTPUT:
    population_density: population / land_area. The population density of a particular area.
    """
    return population / land_area

Lambda Expressions

def multiply(x, y):
    return x * y

Files

# auto closes the file after the indented block has been executed
with open('my_path/my_file.txt', 'r') as f:
    # type is string parameter is the amount of chars to read
    file_data = f.read()

# auto closes the file after the indented block has been executed
# file will be created if it doesn't exist
with open('my_path/my_file.txt', 'r') as f:
    f.write("Hello there!")

with open('my_path/my_file.txt', 'r') as f:
    for line in f:
        print(line)

Zip

list(zip(['a', 'b', 'c'], [1, 2, 3]))
[('a', 1), ('b', 2), ('c', 3)]

Unzip

some_list = [('a', 1), ('b', 2), ('c', 3)]
letters, nums = zip(*some_list)

VirtualEnv

virtualenv --python python3 env
source env/bin/activate
pip3 install -r requirements.txt
python3 ./foo_bar.py
deactivate

Enumerate

letters = ['a', 'b', 'c', 'd', 'e']
for i, letter in enumerate(letters):
    print(i, letter)

Exceptions

while True:
    try:
        x = int(input('Enter a number: '))
        break
    except (ValueError, KeyboardInterrupt  as e):
        print('Thats not a valid number!')
    except(BlahBlahError  as e):
        # some code
        print("Exception occurred: {}".format(e))
    finally:
        print('Attempted Input')