kristofer ha revisionato questo gist . Vai alla revisione
Nessuna modifica
kristofer ha revisionato questo gist . Vai alla revisione
1 file changed, 86 insertions
ifsloopspy.md(file creato)
| @@ -0,0 +1,86 @@ | |||
| 1 | + | ## if statements and loops : the building blocks of your programming | |
| 2 | + | ||
| 3 | + | Here’s a concise explanation of **if statements** and **loops** in Python that might serve as an introductory overview: | |
| 4 | + | ||
| 5 | + | ### Introduction to If Statements and Loops | |
| 6 | + | ||
| 7 | + | Python is a programming language that uses control structures like **if statements**, loops, and conditional expressions. These constructs allow programmers to make decisions or perform repetitive tasks based on certain conditions. | |
| 8 | + | ||
| 9 | + | #### What are If Statements? | |
| 10 | + | ||
| 11 | + | An `if` statement is used to execute code only when a specified condition is true. It’s one of the basic building blocks of any programming language because it allows for decision-making logic. | |
| 12 | + | ||
| 13 | + | **Flow Control Basics:** | |
| 14 | + | ||
| 15 | + | - **Condition**: The first part you write in an `if` statement checks if something is true or false. | |
| 16 | + | - **Action**: Based on whether the condition is met, either execute a block of code (the action) directly after the `if`, or continue to other statements (**else**, `elif`, etc.). | |
| 17 | + | ||
| 18 | + | #### Flow Control with Loops | |
| 19 | + | ||
| 20 | + | Loops are used when you need to repeat a specific set of instructions multiple times. Python has two types: **for loops** and **while loops**. | |
| 21 | + | ||
| 22 | + | 1. **For Loop**: This is used when the number of iterations is known in advance (e.g., "loop 5 times"). | |
| 23 | + | ||
| 24 | + | - Syntax: | |
| 25 | + | ``` | |
| 26 | + | for variable_name in iterable: | |
| 27 | + | execute code | |
| 28 | + | ``` | |
| 29 | + | ||
| 30 | + | 2. **While Loop**: This runs as long as a specified condition is true. | |
| 31 | + | ||
| 32 | + | - Syntax: | |
| 33 | + | ``` | |
| 34 | + | while condition: | |
| 35 | + | execute code | |
| 36 | + | ``` | |
| 37 | + | ||
| 38 | + | Both loops are flow control structures because they allow you to repeat actions until certain conditions are met or not. | |
| 39 | + | ||
| 40 | + | --- | |
| 41 | + | ||
| 42 | + | ### Example of Flow Control in Python | |
| 43 | + | ||
| 44 | + | Here’s an example that demonstrates both `if` statements and loops: | |
| 45 | + | ||
| 46 | + | **Scenario:** You have a list of students with their names, grades, and scores. You want to find the student with the highest grade. | |
| 47 | + | ||
| 48 | + | ```python | |
| 49 | + | students = [ | |
| 50 | + | {'name': 'John', 'grade': 85}, | |
| 51 | + | {'name': 'Jane', 'grade': 90}, | |
| 52 | + | {'name': 'Mike', 'grade': 85} | |
| 53 | + | ] | |
| 54 | + | ``` | |
| 55 | + | ||
| 56 | + | **Your Program:** | |
| 57 | + | ||
| 58 | + | 1. **Loop through each student to find the highest grade and their name.** | |
| 59 | + | 2. If you need to do this programmatically, use a loop. | |
| 60 | + | ||
| 61 | + | ```python | |
| 62 | + | max_grade = -float('inf') | |
| 63 | + | highest_name = '' | |
| 64 | + | ||
| 65 | + | for student in students: | |
| 66 | + | if student['grade'] > max_grade: | |
| 67 | + | max_grade = student['grade'] | |
| 68 | + | highest_name = student['name'] | |
| 69 | + | ||
| 70 | + | # Using an if-else statement to check the maximum grade. | |
| 71 | + | if max_grade == 90: | |
| 72 | + | print("Jane has the highest grade.") | |
| 73 | + | elif max_grade == 85: | |
| 74 | + | print("Both John and Mike have the same highest grade, which is 85.") | |
| 75 | + | else: | |
| 76 | + | print(f"{highest_name} scored {max_grade}.") | |
| 77 | + | ``` | |
| 78 | + | ||
| 79 | + | --- | |
| 80 | + | ||
| 81 | + | ### Why These Concepts Are Important | |
| 82 | + | ||
| 83 | + | - **Decision Making:** `if` statements allow you to make decisions in your code. | |
| 84 | + | - **Repetition:** Loops enable you to repeat tasks until a condition is met, which is useful for automating repetitive actions. | |
| 85 | + | ||
| 86 | + | By mastering these control structures, you can write more complex and efficient programs. If you have any specific questions or need further clarification on this topic, feel free to ask! | |
Più nuovi
Più vecchi