Merge pull request #677 from realpython/python-enumerate

Add materials for enumerate tutorial

Author: brendaweles

python-enumerate/README.md

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+# Python enumerate(): Simplify Loops That Need Counters
+
+This folder contains sample code for the Real Python tutorial [Python enumerate(): Simplify Loops That Need Counters](https://realpython.com/python-enumerate/).

python-enumerate/custom_enumerate.py

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+def my_enumerate(iterable, start=0):
+    n = start
+    for elem in iterable:
+        yield n, elem
+        n += 1
+
+
+seasons = ["Spring", "Summer", "Fall", "Winter"]
+
+print(my_enumerate(seasons))
+print(list(my_enumerate(seasons)))
+print(list(my_enumerate(seasons, start=1)))

python-enumerate/enumerate_alternatives.py

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+from itertools import pairwise
+
+# Advanced Iteration Patterns
+
+cities = ["Graz", "Belgrade", "Warsaw", "Berlin"]
+
+for city, next_city in pairwise(cities):
+    print(f"{city} -> {next_city}")
+
+# Slicing
+
+game_name = "Stardew Valley"
+print(game_name[:4])
+
+# Multi-Sequence Iteration
+
+pets = ["Leo", "Aubrey", "Frieda"]
+owners = ["Bartosz", "Sarah Jane", "Philipp"]
+
+for pet, owner in zip(pets, owners):
+    print(f"{pet} & {owner}")

python-enumerate/line_numbers.py

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+lines = [
+    "This is a\tline",
+    "This line is fine",
+    "Another line with whitespace ",
+]
+
+for lineno, line in enumerate(lines, start=1):
+    if "\t" in line:
+        print(f"Line {lineno}: Contains a tab character.")
+    if line.rstrip() != line:
+        print(f"Line {lineno}: Contains trailing whitespace.")

python-enumerate/runners_v1.py

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+runners = ["Lenka", "Martina", "Gugu"]
+
+for position, name in enumerate(runners):
+    print(position, name)

python-enumerate/runners_v2.py

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+runners = ["Lenka", "Martina", "Gugu"]
+
+for position, name in enumerate(runners, start=1):
+    print(position, name)

python-enumerate/secret_message.py

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+secret_message = "3LAigf7eq 5fhiOnpdDs2 Ra6 nwUalyo.9"
+message = ""
+
+for index, char in enumerate(secret_message):
+    if index % 2:
+        message += char
+
+print(message)

python-enumerate/tasks.py

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+tasks_by_priority = ["Pay Rent", "Clean Dishes", "Buy Milk"]
+
+for index, task in enumerate(tasks_by_priority):
+    if index == 0:
+        print(f"* {task.upper()}!")
+    else:
+        print(f"* {task}")