Sample code for the article on global variables in functions (#380)

* Sample code for the article on global variables in functions

* TR updates, first round

* TR updates, second round

* LE README.md

* TR update

---------

Co-authored-by: KateFinegan <[email protected]>

Author: lpozo

python-use-global-variable-in-function/README.md

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+# Using and Defining Global Variables in Your Python Functions
+
+This folder provides the code examples for the Real Python tutorial [Using and Defining Global Variables in Your Python Functions](https://realpython.com/python-use-global-variable-in-function/).

python-use-global-variable-in-function/account_class.py

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+class Account:
+    def __init__(self, balance=0):
+        self.balance = balance
+
+    def deposit(self, amount):
+        self.balance += amount
+        print(f"Successful deposit: +${amount:,.2f}")
+
+    def withdraw(self, amount):
+        if self.balance - amount > 0:
+            self.balance -= amount
+            print(f"Successful withdrawal: -${amount:,.2f}")
+        else:
+            print("Not enough funds for this transaction")
+
+
+def main():
+    account = Account()
+    while True:
+        operation = input(
+            "What would you like to do?\n"
+            " d) deposit  "
+            " w) withdraw  "
+            " b) balance  "
+            " q) quit\n"
+            "> "
+        )
+        if operation in "dD":
+            amount = float(input("Enter the deposit amount: "))
+            account.deposit(amount)
+        elif operation in "wW":
+            amount = float(input("Enter the withdrawal amount: "))
+            account.withdraw(amount)
+        elif operation in "bB":
+            print(f"Current balance: ${account.balance:,.2f}")
+        elif operation in "qQ":
+            print("Goodbye!")
+            break
+        else:
+            print("Invalid operation. Please try again.")
+
+
+main()

python-use-global-variable-in-function/account_global.py

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+balance = 0
+
+
+def deposit(amount):
+    global balance
+    balance += amount
+    print(f"Successful deposit: +${amount:,.2f}")
+
+
+def withdraw(amount):
+    global balance
+    if balance - amount > 0:
+        balance -= amount
+        print(f"Successful withdrawal: -${amount:,.2f}")
+    else:
+        print("Not enough funds for this transaction")
+
+
+def get_balance():
+    return balance
+
+
+def main():
+    while True:
+        operation = input(
+            "What would you like to do?\n"
+            " d) deposit  "
+            " w) withdraw  "
+            " b) balance  "
+            " q) quit\n"
+            "> "
+        )
+        if operation in "dD":
+            amount = float(input("Enter the deposit amount: "))
+            deposit(amount)
+        elif operation in "wW":
+            amount = float(input("Enter the withdrawal amount: "))
+            withdraw(amount)
+        elif operation in "bB":
+            print(f"Current balance: ${get_balance():,.2f}")
+        elif operation in "qQ":
+            print("Goodbye!")
+            break
+        else:
+            print("Invalid operation. Please try again.")
+
+
+main()

python-use-global-variable-in-function/conf.py

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+config = {
+    "base_url": "http://127.0.0.1:5000/api",
+    "timeout": 30,
+}
+
+
+def update_config(**kwargs):
+    for key, value in kwargs.items():
+        if key in {"api_key", "base_url", "timeout"}:
+            config[key] = value
+        else:
+            raise KeyError(key)

python-use-global-variable-in-function/config.json

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+{
+  "database": {
+    "host": "localhost",
+    "port": 5432,
+    "name": "database.db",
+    "user": "username",
+    "password": "secret"
+  },
+  "api_key": "111222333",
+  "base_url": "https://example.com/api",
+  "timeout": 60
+}

python-use-global-variable-in-function/incrementer.py

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+def increment(value=0):
+    return value + 1
+
+
+counter = increment()
+counter = increment(counter)

python-use-global-variable-in-function/nasa.py

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+import webbrowser
+
+import requests
+
+API_KEY = "DEMO_KEY"
+BASE_URL = "https://api.nasa.gov/planetary"
+TIMEOUT = 3
+
+
+def load_earth_image(date):
+    endpoint = f"{BASE_URL}/apod"
+    try:
+        response = requests.get(
+            endpoint,
+            params={
+                "api_key": API_KEY,
+                "date": date,
+            },
+            timeout=TIMEOUT,
+        )
+    except requests.exceptions.RequestException as e:
+        print(f"Error connecting to API: {e}")
+        return
+
+    try:
+        url = response.json()["url"]
+    except KeyError:
+        print(f"No image available on {date}")
+        return
+
+    webbrowser.open(url)

python-use-global-variable-in-function/setting.py

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+import json
+
+
+def set_config_key(key, value):
+    globals()[key] = value
+
+
+with open("config.json") as json_config:
+    for key, value in json.load(json_config).items():
+        set_config_key(key, value)