Python

Applications & Webpages

• Python IDLE
• Pycharm
• Intellij Idea

• https://peps.python.org/pep-0008/
• https://automatetheboringstuff.com/2e/

Basic Syntax

# Leave a comment by prepending a "#" to your command

# Print "Hello World"
>>> print("Hello World!")
Hello World!

# Echo 3 strings
>>> "Hello" + " " + "World"
'Hello World'

# Add a newline to a value
>>> print("Hello World!\n")
Hello World!


# Escape an escape character
>>> print("Hello World\\n")
Hello World\n

# Single apostrophe is usable inside double-quotes
>>> "Hello 'orld"
"Hello 'orld"

# Escape a double apostrophe
>>> "Hello \"World"
'Hello "World'

Value types

# Find out the type of a value
>>> type (1 + 2)
<class 'int'>

>>> type (4 / 2)
<class 'float'>

>>> type("hello")
<class 'str'>

>>> type(False)
<class 'bool'>

# Set a value as a specific value-type
>>> int(4.0)
4
>>> float(2)
2.0

Basic math

# Add values together
>>> 2 + 3
5

# Two to the power of 3
>>> 2 ** 3
8

# Divide whole numbers
>>> 9 / 2
4.5

# Divide whole number but print the number on the left side of the comma
>>> 9 // 2
4

# Modulo - The remainder after subtracting 2 as many times as you can
>>> 9 % 2
1

# Display the lowest or highest value of a set values
>>> min(5, 1, 8)
1

>>> max(5, 1, 8)
8

True and False

# True and False
>>> True - False
1

>>> False
False

>>> False + False
0

>>> int(False)
0

>>> int(False) + int(True)
1

# Comparisons
>>> 2 < 3
True

>>> 2 > 3
False

>>> 2 == 3
False

>>> 2 != 3
True

Variables

# Define a variable
>>> a = 3

# Display the contents of a variable
>>> a
3

>>> s = "Apple"
>>> s[0]
'A'

Common blocks

if

# If block and expression
if ( n % 2 == 1 ):
    print("Weird")

# if and elif blocks with expressions
if ( n % 2 == 1 ):
    print("Weird")
elif ( n >= 3 and n <= 5 and n % 2 == 0):
    print("Not Weird")

for

# Basic for loop printing each character separately
for char in name:
    print(char)

# For loop that checks for "top" inside words and lists the words
for word in ('stop', 'desktop', 'post', 'top'):
    if 'top' in word:
         print(word)
print('Done.')

# Output list entries using a for loop
names = ["Alex", "Alice", "Baba", "Bertha"]
a_list = [name for name in names if name[0] == "A"]
print(a_list)

Range

# Print digits 0 through 3 using the range function
for number in range(3):
    print(number)
    

# Print digits 0 through 3 but don't output on a newline
for number in range(3):
    print(number, end=" ")
    
# Print digit for every 2 numbers between 0 and 11, starting from 0
for number in range(0, 11, 2):
    print(number, end=" ")