Data in JSON Style

Most APIs return JSON, which becomes nested dict/list in Python.

Example JSON-like structure

data = {
  "users": [
    {"id": 1, "profile": {"name": "Tom"}},
    {"id": 2, "profile": {"name": "Sarah"}},
  ]
}

Read nested data safely

users = data.get("users", [])
for u in users:
    name = u.get("profile", {}).get("name", "Unknown")
    print(name)

Transform: build id -> name map

id_to_name = {}
for u in data.get("users", []):
    uid = u.get("id")
    name = u.get("profile", {}).get("name")
    if uid is not None and name is not None:
        id_to_name[uid] = name

print(id_to_name)

Graph: JSON mapping

flowchart LR
  A[users list] --> B[loop]
  B --> C[id]
  B --> D[name]
  C --> E[dict map]
  D --> E

Remember

• JSON becomes dict + list
• Use get() to avoid KeyError
• Building maps is a common real-world pattern