Merge pull request #671 from realpython/python-t-strings

Sample code for the article on t-strings

Author: brendaweles

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():
+    "Uncomment in Python 3.14+"
+    # return t"Hello, {await get_name()}!"
+
+
+async def main():
+    greeting = await greeting_template()
+    print(greeting)
+
+
+asyncio.run(main())

python-t-strings/logging_message.py

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+import json
+import logging
+from string.templatelib import Template
+
+logging.basicConfig(level=logging.INFO, format="%(message)s")
+
+
+class TemplateMessage:
+    def __init__(self, template):
+        if not isinstance(template, Template):
+            raise TypeError("t-string expected")
+        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)}"
+
+
+# Uncomment in Python 3.14+
+# 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
+from string.templatelib import Template
+
+
+def generate_safe_html(template):
+    if not isinstance(template, Template):
+        raise TypeError("t-string expected")
+    parts = []
+    for item in template:
+        if isinstance(item, str):
+            parts.append(item)
+        else:
+            parts.append(html.escape(item.value))
+    return "".join(parts)
+
+
+# Uncomment in Python 3.14+
+# 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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+from string.templatelib import Template
+
+
+def sanitized_sql(template):
+    if not isinstance(template, Template):
+        raise TypeError("t-string expected")
+    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)
+
+
+# Uncomment in Python 3.14+
+# username = "john'); DROP TABLE students;--"
+# template = t"SELECT * FROM students WHERE name = {username}"
+# query, params = sanitized_sql(template)
+# print("Sanitized SQL Query:", query)
+
+# print("Parameters:", params)

python-t-strings/to_strings.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)
+
+
+# Uncomment in Python 3.14+
+# price = 234.8765
+# print(to_string(t"The price is ${price:.2f}"))
+
+# header = "Report"
+# print(to_string(t"{header:=^20}"))