07_control_flow.md

7. Control flow

Source: src/csharp_to_python_learning/concepts/02_data_and_flow/topic_07_control_flow.py

What C# developers usually expect C# developers usually expect explicit type declarations, predictable object lifetimes, and compile-time guidance.

C# example Simple equivalent:

for (var n = 0; n < 3; n++)
{
    if (n == 1) continue;
    Console.WriteLine($"value {n}");
}

Advanced equivalent:

var target = 7;
var found = false;
foreach (var n in new[] { 1, 3, 5 })
{
    if (n == target)
    {
        Console.WriteLine("found");
        found = true;
        break;
    }
}
if (!found) Console.WriteLine("not found");

Simple Python example from this file

for n in range(3):
    if n == 1:
        continue
    print("value", n)

Advanced Python example from this file

target = 7
for n in [1, 3, 5]:
    if n == target:
        print("found")
        break
else:
    print("not found")

Python equivalent Python approaches this concept with less ceremony: Python control flow favors readability with indentation and expressive constructs like for ... else. You still keep production discipline through tests, typing, and tooling.

Detailed explanation for C# developers Python control flow favors readability with indentation and expressive constructs like for ... else. In practice, combine this with logging, tests, and type hints so the flexibility does not turn into ambiguity. Prefer small functions, clear data boundaries, and explicit contracts where behavior matters.

Common mistakes for C# developers

1. Assuming C# defaults apply directly in Control flow without checking Python runtime behavior.
2. Skipping tests because dynamic code feels simpler at first; regressions grow quickly without guardrails.

Exercises

1. Rewrite one recent C# snippet in Python using this concept: Control flow.
2. Add input validation, type hints, and one pytest test for the rewritten snippet.

Expected output

• value 0
• not found