PART 1 - Python Tutorial | Variables and Data Types in Python
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The document provides an introduction to variables and data types in Python, covering topics such as string and numerical data types, functions, and the importance of naming variables correctly. It explains the syntax rules, common errors, and built-in functions associated with various data types, along with examples to illustrate these concepts. Additionally, it discusses the use of constants, lists, and the potential for multiple assignments in Python programming.
PART 1 - Python Tutorial | Variables and Data Types in Python
- 1. PART 1 VARIABLES AND DATA TYPES IN PYTHON • PART 0 – Installing python and syllabus • Playlist link in description • WANT TO LEARN PYTHON PROGRAMMING? (SUBTITLES) • SUBSCRIBE • TELEGRAM – FreeCodeSchool • Twitter – shivammitra4 • LinkedIn – shivammitra • Link in description
- 2. CONTENT • What are variables ? • String data type • Numerical data type • Examples
- 3. VARIABLES IN MATHS • A symbol used to represent a numerical value which can change • 2x = y + 1 ( Algebra ) • x = 1, y = 1 • x = 2, y = 3 • Ten years from now, Rohit will be three times older than he is today. What is his current age?
- 4. WHAT ARE VARIABLES • Variables are used to store data • These data are stored in main memory when you run the program • Programming = data + logic • Different data types in python • Numbers • Strings • Lists • Tuple • Dictionary
- 5. A SIMPLE EXAMPLE • What is print() here ? • What does it do ?
- 6. WHAT ARE FUNCTIONS IN MATHS ? • Takes inputs and gives an output depending on the input • f(x) = x^2 • f(1) = 1 • f(2) = 4 • Programming functions also do the same. • Takes input and returns output ( not always ) • Many built-in functions are present in python • print() is one example – prints the input on screen • More about functions in a separate video
- 7. WHY SHOULD I USE VARIABLES ?
- 8. • Using variables makes programs simpler • Reduces repeated work
- 9. Naming Variables • Can you give any name to the variables ? • What are errors ?
- 10. WHAT ARE ERRORS IN PYTHON ? • My name is Shivam vs Is name Shivam my ? • My nam is Shivam vs My name is Shivam ? • My name are Shivam vs My name is Shivam ? • Every language has a syntax or a set of rules to follow while writing it • Python also has a syntax • If you do not follow it, you will get errors. • More about ”errors in python” in a separate video
- 12. RULE 1 - Variable names can contain only letters, numbers, and underscores. They can start with a letter or an underscore, but not with a number.
- 13. SUPPOSE YOU WANT TO WRITE TWO DIFFERENT MESSAGES ?
- 15. RULE 2 - Spaces are not allowed in variable names, but underscores can be used to separate words in variable names.
- 16. RULE 3 - Avoid using Python keywords and function names as variable names; that is, do not use words that Python has reserved for a particular programmatic purpose, such as the word print.
- 17. WHAT ARE KEYWORDS IN PYTHON? • These are reserved words in python which are used to define the syntax of python language. • In English, “is”, “the”, “you” etc. are reserved words which defines the grammar. • Keywords have different meaning for Python language. • Do not use them in your variables or function names.
- 18. LIST OF KEYWORDS IN PYTHON
- 20. BUILT-IN FUNCTIONS IN PYTHON
- 21. SOME OTHER IMPORTANT POINTS TO NOTE • Variable names should be short but descriptive. • name is better than writing n • message is better than writing m or my_name_message • Be careful when using the lowercase letter l and the uppercase letter O because they could be confused with the numbers 1 and 0.
- 22. It can take some practice to learn how to create good variable names, especially as your programs become more interesting and complicated. As you write more programs and start to read through other people’s code, you’ll get better at coming up with meaningful names.
- 23. AVOIDING NAME ERRORS WHEN USING VARIABLES
- 24. FINDING THE DATA TYPE OF A VARIABLE • Use type() built-in function
- 26. WHAT ARE STRINGS ? • A string is a series of characters • Characters – alphabets, digits, special characters, white spaces • Anything inside quotes is considered a string in Python • You can use single or double quotes around your strings
- 29. SINGLE QUOTE VS DOUBLE QUOTE ? • You can use any of these • Be consistent • Exceptions – print these text on screen: • The language 'Python' is named after Monty Python, not the snake. • I told my friend, "Python is my favorite language!"
- 30. ASSIGNMENT: Try to find out if it is possible to print first message by using single quotes and second by using double quotes and how ?
- 33. • print() vs message.lower() • These built-in functions are specific to strings. • print() is specific to multiple data types • The dot(.) operator acts on the variable and converts it into upper/lower cases • The original data doesn’t change
- 34. TITLE FUNCTION • Converts the first character of each word into upper case
- 35. LEN FUNCTION • Outputs the length of the string • A single character is of length 1 • Characters can be alphabets or digits or punctuation or white spaces
- 36. STRIP FUNCTIONS – strip(), lstrip(), rstrip() • Remove the extra whitespaces from a string
- 37. rstrip() – remove whitespace at right end
- 38. lstrip() – remove whitespace from left end
- 39. strip() – remove spaces from both ends
- 40. USING VARIABLES INSIDE A STRING
- 41. COMBINE THESE TWO TO PRODUCE FULL NAME
- 42. Use f-strings • Feature is available from python 3.6 • Start string with f – f stands for format • Put braces around variable name
- 46. Adding Whitespace to Strings with Tabs or Newlines • In programming, whitespace refers to any nonprinting character, such as spaces, tabs, and end-of-line symbols. • You can use whitespace to organize your output so it’s easier for users to read.
- 47. Add a tab to your text
- 48. Add newline to your text
- 50. What are numbers ? • Integers = 1, 2, 3 • Floats = 1.2, 2.55 • These data are used very frequently in a program.
- 51. INTEGERS • You can add, subtract, multiply and divide python integers
- 53. • Python uses two multiplication symbols to represent exponents.
- 54. MULTIPLE OPERATORS IN ONE EXPRESSION
- 55. • The spacing in these examples has no effect on how Python evaluates the expressions • Clarity • More about precedence of operators in a future video
- 56. FLOATS • Python calls any number with a decimal point a float. • This term is used in most programming languages, and it refers to the fact that a decimal point can appear at any position in a number. • Example: 1.2, 12.35
- 58. This happens in all languages and is of little concern. Python tries to find a way to represent the result as precisely as possible, which is sometimes difficult given how computers have to represent numbers internally.
- 62. MULTIPLE ASSIGNMENTS • You can assign values to more than one variable using just a single line. • This can help shorten your programs and make them easier to read. • You’ll use this technique most often when initializing a set of numbers.
- 63. CONSTANTS IN PYTHON • A constant is like a variable whose value stays the same throughout the life of a program. • Python doesn’t have built-in constant types, but Python programmers use all capital letters to indicate a variable should be treated as a constant and never be changed.
- 64. LISTS IN PYTHON