Learning Python

Learn The Basic

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I had taken serveral python courses before and wrote basic loop and if statements but actually applying coding prinicpals to tackle a problem/solution is a whole different story.

Learn the basics throughly and be patient with the process.

Python Terminal Program

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Tips for real-world application

1. When writing code follow the best practices outlined in PEP20 - Zen of Python

2. Check any incoming input strings and prep to remove empty spaces with strip() remember we’re humans and sometimes people type added an extra space at the end by accident.

3. Use join to save time for concatenating (combining) a list of str values.

     #Example
     color_list = ['red','blue']
     print('$'.join(color_list))
   

4. Using the help() function to print all the properties of a given class or method.

      #Example
      #Print help for the str method on the python console
      help(str)
         
   

5. To check builtin-in modules loaded use the dunder method and output the properties.

   Loop through __builtins__.__dict__ and review modules for additional info.

      #Example
      for x in __builtins__.__dict__:
            print(x)
   

   or with comprehension

      #Example
      [print(x) for x in __builtins__.__dict__]
   

6. Practice using python comprehension to simplify code. .

7. Use a package manager for python to orchestrate module installation, I perfer poetry. This auto install dependicies for the code to work outside of the system global

8. Having a good understanding of the fundamental topics such as methods, class, and functions will significantly increase your ability to develop/brainstorm solutions for the attended problem.

      #Example
      #Using open(), str(), list() methods to modify a given csv file.
   
      with open('file.csv',) as csvfile:
      content = csv.reader(csvfile, delimiter=',')
      for row in content:
      for color in row:
            print(color)   
   
   

Basic Knowledege

• When creating a variable, it must start as a letter or an underscore
• Python treats characters differently depending on the class, i.e. ‘1’ is not 1
• When in doubt reference Python documentation

Manipluating the string = str

Any string / str can be modified, there are many str.methods at your disposal to transform the characters to your need.

String Splicing

Essentially selecting a character by picking it’s positional place in the word. Remember positional value starts from 0 and empty value (i.e. blank space) counts.

#Example
word = 'Hello World!'
print(word[0])
print(word[1])
print(word[11])

String Splicing II

You can also iterate over strings with a verbose method [a:b:c]

• a is the starting position
• b is the ending position
• c is the frequency

Note:

• When using this method positional value start at 1.
• Default starting value is 0, and frequency value is 1, [0::1]
• To print in reverse order use the frequency value at -1, [::-1]

#Example
word = 'Hello World!'
print(word[1:5:])
print(word[::2])
print(word[::-1])

String Alignment

You can align string depending on the position of a give text value with the str:<value

#Example
my_string = '{string1:>1}'
my_string2 = '{string1:>10}'
print(my_string.format(string1='Hello'))
print(my_string2.format(string1='Hello'))

Exceptions

Are used to handled data that does not mesh with your code. Example, you want a user to enter a data in string format, you can use the Exception class dervived from the BaseException to throw and error.