Sample code for the article on t-strings

Author: lpozo

python-t-strings/README.md

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+# Python 3.14 Preview: Template Strings (T-Strings)
+
+This folder provides the code examples for the Real Python tutorial [Python 3.14 Preview: Template Strings (T-Strings)](https://realpython.com/python-t-string/).

python-t-strings/asynchronous.py

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+import asyncio
+
+
+async def get_name():
+    # Simulate an asynchronous operation
+    await asyncio.sleep(1)
+    return "Pythonista"
+
+
+async def greeting_template():
+    return t"Hello, {await get_name()}!"
+
+
+async def main():
+    greeting = await greeting_template()
+    print(greeting)
+
+
+asyncio.run(main())

python-t-strings/emails.py

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+def fill_order_template(lang, name, order_id, date):
+    templates = {
+        "en": t"Thank you, {name}! Your order #{order_id} will arrive on {date}.",
+        "es": t"Gracias, {name} Su orden No. {order_id} arribará el próximo {date}.",
+        "fr": t"Merci, {name}! Votre commande n° {order_id} arrivera le {date}.",
+    }
+    return templates.get(lang, templates["en"])
+
+
+def generate_order_email(template):
+    parts = []
+    for item in template:
+        if isinstance(item, str):
+            parts.append(item)
+        else:
+            parts.append(str(item.value))
+    return "".join(parts)
+
+
+template = fill_order_template("en", "Alice", 12345, "June 10")
+email = generate_order_email(template)
+print(email)

python-t-strings/i18n.py

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+name = input("Enter your name please: ")
+
+translations = {
+    "en": t"Hello, {name}! Welcome back!",
+    "es": t"¡Hola, {name}! ¡Bienvenido de vuelta!",
+    "fr": t"Bonjour, {name}! Bon retour!"
+}
+
+
+def get_localized_greeting(lang):
+    template = translations.get(lang, translations["en"])
+    parts = []
+    for item in template:
+        if isinstance(item, str):
+            parts.append(item)
+        else:
+            parts.append(item.value)
+    return "".join(parts)
+
+
+print(get_localized_greeting("en"))
+print(get_localized_greeting("es"))
+print(get_localized_greeting("fr"))

python-t-strings/logging_message.py

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+import json
+import logging
+
+logging.basicConfig(level=logging.INFO, format='%(message)s')
+
+
+class TemplateMessage:
+    def __init__(self, template):
+        self.template = template
+
+    @property
+    def message(self):
+        parts = []
+        for item in self.template:
+            if isinstance(item, str):
+                parts.append(item)
+            else:
+                parts.append(str(item.value))
+        return "".join(parts)
+    
+    @property
+    def values_dict(self):
+        values = {}
+        for item in self.template:
+            if not isinstance(item, str):
+                values[item.expression] = item.value
+        return values
+
+    def __str__(self):
+        return f"{self.message} >>> {json.dumps(self.values_dict)}"
+
+
+action, amount, item = "refund", 7, "keyboard"
+msg_template = TemplateMessage(t"Process {action}: {amount:.2f} {item}")
+logging.info(msg_template)

python-t-strings/scape_html.py

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+import html
+
+
+def render_safe_html(template):
+    parts = []
+    for item in template:
+        if isinstance(item, str):
+            parts.append(item)
+        else:
+            parts.append(html.escape(item.value))
+    return "".join(parts)
+
+
+username = "<script>alert('Hacked!')</script>"
+template = t"<p>Hello, {username}!</p>"
+
+safe_html = render_safe_html(template)
+print(safe_html)

python-t-strings/sql.py

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+def sanitized_sql(template):
+    parts = []
+    params = []
+
+    for item in template:
+        if isinstance(item, str):
+            parts.append(item)
+        else:
+            parts.append("?")
+            params.append(item.value)
+
+    query = "".join(parts)
+    return query, tuple(params)
+
+
+template = t"SELECT * FROM students WHERE name = '{username}';"
+query, params = sanitized_sql(template)
+print("Sanitized SQL Query:", query)
+print("Parameters:", params)

python-t-strings/template_to_string.py

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+def to_string(template):
+    parts = []
+    for part in template:
+        if isinstance(part, str):
+            parts.append(part)
+        else:
+            value = {
+                "a": ascii,
+                "r": repr,
+                "s": str}.get(part.conversion, lambda _: part.conversion)(part.value)
+            value = format(value, part.format_spec)
+            parts.append(value)
+    return "".join(parts)
+
+
+price = 234.8765
+print(to_string(t"The price is ${price:.2f}"))
+print(to_string(t"The price is ${price!s:.2f}"))

python-t-strings/to_stirngs.py

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+def to_string(template):
+    def convert(value, conversion):
+        func = {"a": ascii, "r": repr, "s": str}.get(conversion, lambda x: x)
+        return func(value)
+
+    parts = []
+    for item in template:
+        if isinstance(item, str):
+            parts.append(item)
+        else:
+            value = format(convert(item.value, item.conversion), item.format_spec)
+            parts.append(value)
+    return "".join(parts)
+
+
+price = 234.8765
+print(to_string(t"The price is ${price:.2f}"))
+
+header = "Report"
+print(to_string(t"{header:=^20}"))

python-t-strings/traverse_items.py

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+from string.templatelib import Interpolation
+
+name = "Pythonista"
+site = "realpython.com"
+template = t"Hello, {name}! Welcome to {site}!"
+
+# for item in template:
+#     print(item)
+
+# for s in template.strings:
+#     print(s)
+
+for value in template.values:
+    print(value)
+
+debit = 300.4344
+credit = 450.5676
+balance = credit - debit
+template = t"Credit: {credit:.2f}, Debit: {debit:.2f}, Balance: {balance:.2f}"
+
+
+# def build_report(template):
+#     parts = ["Account Report:\n"]
+#     for item in template:
+#         if isinstance(item, str):
+#             parts.append(item.strip(", ").upper())
+#         else:
+#             parts.append(f"> ${item.value:{item.format_spec}}")
+#         parts.append("\n")
+#     return "".join(parts)
+
+
+def build_report(template):
+    parts = ["Account Report:\n"]
+    for item in template:
+        match item:
+            case str() as s:
+                parts.append(s.strip(", ").upper())
+            case Interpolation() as i:
+                parts.append(f"> ${i.value:{i.format_spec}}")
+        parts.append("\n")
+    return "".join(parts)
+
+
+report = build_report(template)
+print(report)