nest-tree

A Python tool to visualize the structure of nested dictionaries and lists in a tree-like format, similar to the Unix tree command.

Installation

pip install nest-tree

Usage

Tl;dr

from nest_tree import tree

tree(data)

tree(data, leaf="none", level=None, print_output=True, return_output=False)

• Parameters:
  • data (dict | list): The nested dictionary or list to visualize.
  • leaf (str): Controls leaf display - "none" (default), "value", or "type".
  • level (int | None): Maximum depth. If None, expand fully.
  • print_output (bool): If True, print to stdout. Default: True.
  • return_output (bool): If True, return what would be printed as a string. Default: False (in order to avoid busy output in interactive REPLs like IPython).
• Return:
  • If return_output is True: the output is returned as a string. No return value otherwise.

Example

Consider the following nested list/dict

data = {
    "fruits": ["apple", "banana"],
    "vegetables": {
        "green": ["lettuce", "spinach"],
        "root": ["carrot", "potato"],
    },
    "requirement": [
        {"type": "protein", "amount": 100, "unit": "g"},
        {"type": "vitamin C", "amount": 80, "unit": "mg"}
    ]
}

tree(data, level=2)

├── fruits
│   ├── [0]
│   └── [1]
├── vegetables
│   ├── green
│   └── root
└── requirement
    ├── [0]
    └── [1]

tree(data, leaf="type")

├── fruits
│   ├── [0]
│   │   └── <class 'str'>
│   └── [1]
│       └── <class 'str'>
├── vegetables
│   ├── green
│   │   ├── [0]
│   │   │   └── <class 'str'>
│   │   └── [1]
│   │       └── <class 'str'>
│   └── root
│       ├── [0]
│       │   └── <class 'str'>
│       └── [1]
│           └── <class 'str'>
└── requirement
    ├── [0]
    │   ├── type
    │   │   └── <class 'str'>
    │   ├── amount
    │   │   └── <class 'int'>
    │   └── unit
    │       └── <class 'str'>
    └── [1]
        ├── type
        │   └── <class 'str'>
        ├── amount
        │   └── <class 'int'>
        └── unit
            └── <class 'str'>

tree(data, leaf="value")

├── fruits
│   ├── [0]
│   │   └── apple
│   └── [1]
│       └── banana
├── vegetables
│   ├── green
│   │   ├── [0]
│   │   │   └── lettuce
│   │   └── [1]
│   │       └── spinach
│   └── root
│       ├── [0]
│       │   └── carrot
│       └── [1]
│           └── potato
└── requirement
    ├── [0]
    │   ├── type
    │   │   └── protein
    │   ├── amount
    │   │   └── 100
    │   └── unit
    │       └── g
    └── [1]
        ├── type
        │   └── vitamin C
        ├── amount
        │   └── 80
        └── unit
            └── mg

Running Tests

python -m unittest tests.test_tree -v