Python Basics

This article contains my notes on the Python programming language as of Python 3.x.

Operators

See Python Operators

Built-in Functions

https://docs.python.org/3/library/functions.html

Strings

Convert a List of Strings to a String

list1 = ['Hello', 'World']
print(' '.join(list1))
# Output: 
# Hello World

When used with a list of elements, which are not of type string, the elements need to be converted to string first.

Template Strings

a = "Munich"
b = "Frankfurt"
c = "Berlin"

# Template string
template = "We are doing a road trip from {} through {} to {}"
print(template.format(a, b, c))

# equivalent to:
print("We are doing a road trip from {} through {} to {}".format(a, b, c))

# equivalent to:
print("We are doing a road trip from {place1} through {place2} to {place3}".format(place3=c, place2=b, place1=a))

F-Strings

a = "Munich"
b = "Frankfurt"
c = "Berlin"

# f-String
print(f"We are doing a road trip from {a} through {b} to {c}")

Further reading:

• https://realpython.com/python-string-formatting/
• https://docs.python.org/3/whatsnew/3.12.html#pep-701-syntactic-formalization-of-f-strings
• https://docs.python.org/3/library/string.html#template-strings

Format Specification

Format Number to string with one decimal place and a % as suffix. Not needed decimal places rounded as follows:

print("{:.1f}%".format(2.25))   #output: 2.2%
print("{:.1f}%".format(2.26))   #output: 2.3%

See https://docs.python.org/3/library/string.html#formatspec

Classes and Object Methods

https://docs.python.org/3/reference/datamodel.html#emulating-container-types

Command Line

https://docs.python.org/3/using/cmdline.html

Executing functions from command line

A function called myfunction from myscript.py can be executed directly from the command line like this:

python -c 'import myscript; myscript.myfunction(var1, var2)

Modules

See Python Built-in Modules