Control Flow - Choosing a Path in the Jungle

Welcome, @name! We stand at a fork in the trails. One path leads across a river, the other through dense forest. A good explorer must make decisions based on conditions. In Python, conditional statements are used to make decisions: `if`, `elif`, and `else`.

The if Statement - If the Condition Is Met

The word `if` checks a condition. If the condition is `True`, Python executes the indented block of code. If it's `False` - it skips it.

1temperature = 35
2
3if temperature > 30:
4    print("🔥 It's hot! Stay in the shade.")
5    print("Remember to drink water.")

Notice three things: after the condition we put a colon `:`, and the code to execute is indented (usually 4 spaces). This indentation tells Python: "this belongs to the condition." A condition is an expression that returns `True` or `False` - exactly what you learned with comparison operators.

if / else - Two Paths

Often we want to do one thing when a condition is met and something else when it's not. That's what `else` ("otherwise") is for.

1water_supply = 2   # liters
2
3if water_supply >= 3:
4    print("💧 We have enough water for today.")
5else:
6    print("⚠️ Low on water! We must find a source.")

Python checks the condition at `if`. If it's `True` - it runs the `if` block. If `False` - it jumps to the `else` block. Exactly one of the two paths always runs.

if / elif / else - Multiple Paths

But what if there are more than two paths? Imagine evaluating temperature: hot, pleasant, or cold. That's what `elif` is for (short for "else if" - "otherwise if"). You can add as many `elif` blocks as you need.

1temperature = 22
2
3if temperature > 30:
4    print("🔥 It's hot in the jungle!")
5elif temperature >= 15:
6    print("🌤️ Pleasant temperature for marching.")
7elif temperature >= 5:
8    print("🧥 Chilly, grab a jacket.")
9else:
10    print("❄️ Cold! Light a campfire.")

Python checks conditions one by one, top to bottom. It runs the block of the first condition that is `True` and skips the rest. If no condition matches, it runs the `else` block (if one exists). That's why order matters - we check from the most specific conditions.

Combining Conditions in Decisions

Remember the logical operators `and`, `or`, `not`? They work great inside conditional statements:

1temperature = 28
2is_raining = False
3
4if temperature > 20 and not is_raining:
5    print("✅ Perfect conditions - off on safari!")
6else:
7    print("🏕️ We stay in camp.")

Practice

Write a program that evaluates whether an animal is dangerous based on its weight. Complete the missing conditions in the editor:

Summary

In this lesson you learned to make decisions in code:

• ✅ `if` - runs code when the condition is `True`
• ✅ `else` - runs code when the condition is `False`
• ✅ `elif` - checks further conditions when previous ones were `False`
• ✅ The meaning of the colon `:` and indentation in blocks
• ✅ Combining conditions with `and`, `or`, `not`

In the next lesson Darwin will teach you loops - how to repeat actions without rewriting code! 🔁🌴