{ "cells": [ { "cell_type": "markdown", "id": "ch03-title", "metadata": {}, "source": [ "# Control Flow" ] }, { "cell_type": "markdown", "id": "ch03-overview", "metadata": {}, "source": [ "Control flow lets a program decide what to do next. This chapter introduces the branching and looping structures that turn straight-line code into programs that respond to data.\n", "\n", "- Conditional statements with `if`, `elif`, and `else`\n", "- `for` loops for iterating over data\n", "- `while` loops for condition-based repetition\n", "- Loop-control keywords for special cases\n" ] }, { "cell_type": "markdown", "id": "0300-video", "metadata": {}, "source": [ "

Chapter Video

\n", "\n", "This overview introduces Boolean expressions and conditional branches with if, elif, and else.\n", "\n", "```{raw} html\n", "\n", "```\n", "\n", "> *[Python Tutorial for Beginners 6: Conditionals and Booleans - If, Else, and Elif Statements (16:28)](https://youtube.com/watch?v=DZwmZ8Usvnk) by Corey Schafer*\n", ">\n", "> Hosted on YouTube; property of its original creator, embedded here for educational reference only." ] }, { "cell_type": "markdown", "id": "ch03-goals", "metadata": {}, "source": [ "

Learning Objectives

\n", "\n", "By the end of this chapter, you will be able to:\n", "\n", "1. Use conditional statements to choose between branches of code\n", "2. Write `for` and `while` loops for repeated work\n", "3. Use `break`, `continue`, and `pass` intentionally\n", "4. Trace how control moves through nested branches and loops\n" ] }, { "cell_type": "markdown", "id": "ch03-flow", "metadata": {}, "source": [ "

Chapter Flow

\n", "\n", "```{container} chapter-flow\n", "1. {doc}`0301-conditionals`\n", "2. {doc}`0302-iteration`\n", "```" ] }, { "cell_type": "markdown", "id": "ch03-glossary", "metadata": {}, "source": [ "

Glossary

\n", "\n", "| # | Term | Explanation |\n", "|---:|---|---|\n", "| 1 | Control flow | The order in which a program runs statements. |\n", "| 2 | Conditional statement | A statement that chooses whether to run code based on a condition. |\n", "| 3 | Boolean expression | An expression that evaluates to `True` or `False`. |\n", "| 4 | Branch | One possible path through a conditional statement. |\n", "| 5 | `if` statement | A conditional statement that runs a block only when its condition is true. |\n", "| 6 | `else` clause | The branch that runs when the `if` condition is false. |\n", "| 7 | `elif` clause | A chained conditional branch that tests another condition. |\n", "| 8 | Nested conditional | A conditional statement placed inside another conditional statement. |\n", "| 9 | Conditional expression | A compact expression that chooses between two values. |\n", "| 10 | Iteration | Repeating a block of code. |\n", "| 11 | Iterable | An object that can provide its items one at a time. |\n", "| 12 | Iterator | An object that tracks its position while producing items one at a time. |\n", "| 13 | `for` loop | A loop that repeats once for each item in an iterable. |\n", "| 14 | `range` | A built-in type commonly used to generate integer sequences for loops. |\n", "| 15 | `while` loop | A loop that repeats while a condition remains true. |\n", "| 16 | Sentinel | A special value that signals when a data-controlled loop should stop. |\n", "| 17 | Infinite loop | A loop whose condition never becomes false unless something interrupts it. |\n", "| 18 | `break` statement | A statement that exits the nearest enclosing loop immediately. |\n", "| 19 | `continue` statement | A statement that skips the rest of the current loop iteration. |\n", "| 20 | Running total | A variable updated inside a loop to accumulate a total such as total rainfall. |\n", "| 21 | Accumulator pattern | A loop pattern that initializes a variable before the loop, updates it on each iteration, and uses the result after the loop. |\n", "| 22 | Trace table | A table that records the value of each variable after every loop iteration, used to check how a loop behaves. |\n", "| 23 | Chained conditional | A conditional statement with one or more `elif` clauses that tests conditions in order and runs only the first true branch. |\n", "| 24 | `pass` statement | A statement that does nothing, used as a placeholder where Python requires a block. |\n", "| 25 | Loop variable | The variable in a `for` loop header that holds the current item on each iteration. |\n", "| 26 | Nested loop | A loop inside the body of another loop; the inner loop finishes all its iterations for each iteration of the outer loop. |\n", "| 27 | Off-by-one error | A bug where a loop or index runs one step too many or too few, often from using `<=` where `<` is needed. |\n", "| 28 | `enumerate` | A built-in function that produces each item of an iterable together with its index. |\n", "| 29 | `zip` | A built-in function that pairs up items from two or more iterables so you can loop over them in parallel. |\n" ] }, { "cell_type": "markdown", "id": "0300-slides", "metadata": {}, "source": [ "

Chapter Overview Slides

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