added materials for How to Use the Claude API in Python for AI-Powere…

…d Applications
realpython · bzaczynski · May 9, 2026 · Mar 26, 2026 · Apr 2, 2026 · Apr 17, 2026
commit bcf7bfdf5526d794995721fe7d6bb4269326dd53
diff --git a/how-to-use-claude-api-in-python/basic_claude_call.py b/how-to-use-claude-api-in-python/basic_claude_call.py
@@ -0,0 +1,13 @@
+import anthropic
+
+client = anthropic.Anthropic()
+
+response = client.messages.create(
+    model="claude-sonnet-4-5",
+    max_tokens=1024,
+    messages=[
+        {"role": "user", "content": "What is the Zen of Python?"}
+    ],
+)
+
+print(response.content[0].text)
diff --git a/how-to-use-claude-api-in-python/coding_assistant.py b/how-to-use-claude-api-in-python/coding_assistant.py
@@ -0,0 +1,22 @@
+import anthropic
+
+client = anthropic.Anthropic()
+
+system_prompt = """
+You are a Python coding assistant. You only answer questions about Python.
+If the user asks about any other programming language or unrelated topic,
+politely explain that you can only help with Python questions.
+"""
+
+user_input = input("Ask me anything about Python: ")
+
+response = client.messages.create(
+    model="claude-sonnet-4-5",
+    max_tokens=1024,
+    system=system_prompt,
+    messages=[
+        {"role": "user", "content": user_input}
+    ],
+)
+
+print(f"\n{response.content[0].text}")
diff --git a/how-to-use-claude-api-in-python/requirements.txt b/how-to-use-claude-api-in-python/requirements.txt
@@ -0,0 +1,2 @@
+anthropic
+pydantic
diff --git a/how-to-use-claude-api-in-python/structured_output_1.py b/how-to-use-claude-api-in-python/structured_output_1.py
@@ -0,0 +1,38 @@
+import anthropic
+import json
+
+client = anthropic.Anthropic()
+
+response = client.messages.create(
+    model="claude-sonnet-4-5",
+    max_tokens=1024,
+    system="You are a Python coding assistant.",
+    messages=[
+        {
+            "role": "user",
+            "content": "Write a Python function that adds two numbers.",
+        }
+    ],
+    output_config={
+        "format": {
+            "type": "json_schema",
+            "schema": {
+                "type": "object",
+                "properties": {
+                    "function_name": {"type": "string"},
+                    "code": {"type": "string"},
+                    "explanation": {"type": "string"},
+                },
+                "required": ["function_name", "code", "explanation"],
+                "additionalProperties": False,
+            },
+        }
+    },
+)
+
+result = json.loads(response.content[0].text)
+
+print("--- Approach 1: Hand-written JSON schema ---")
+print(f"Function: {result['function_name']}")
+print(f"\nCode:\n{result['code']}")
+print(f"\nExplanation: {result['explanation']}")
diff --git a/how-to-use-claude-api-in-python/structured_output_2.py b/how-to-use-claude-api-in-python/structured_output_2.py
@@ -0,0 +1,31 @@
+import anthropic
+
+from pydantic import BaseModel
+
+
+class FunctionDescription(BaseModel):
+    function_name: str
+    code: str
+    explanation: str
+
+client = anthropic.Anthropic()
+
+response = client.messages.parse(
+    model="claude-sonnet-4-5",
+    max_tokens=1024,
+    system="You are a Python coding assistant.",
+    messages=[
+        {
+            "role": "user",
+            "content": "Write a Python function that adds two numbers.",
+        }
+    ],
+    output_format=FunctionDescription,
+)
+
+result = response.parsed_output
+
+print("--- Approach 2: Pydantic + client.messages.parse() ---")
+print(f"Function: {result.function_name}")
+print(f"\nCode:\n{result.code}")
+print(f"\nExplanation: {result.explanation}")