decision-tree-analysis

1> **Source**: [https://github.com/aipoch/medical-research-skills](https://github.com/aipoch/medical-research-skills)
2 
3# Decision Tree Analysis
4 
5Use this skill to train a decision tree model from a tabular file and export feature importance ranking results.
6 
7## Use This Skill When
8 
9- You need a decision tree workflow in R for either classification or regression.
10- You need feature importance ranking as a table and a figure.
11- You need a command-line workflow with parameter validation and standardized output folders.
12 
13## Primary Command
14 
15```bash
16Rscript scripts/main.R \
17  --data_file <input_file> \
18  --target_var <target_column> \
19  --task_type <auto|classification|regression> \
20  --output_dir <output_dir>
21```
22 
23## Prerequisites
24 
25- `Rscript` is available in the shell.
26- Required R packages: `optparse`, `data.table`, `rpart`.
27- Install missing packages with `Rscript -e 'install.packages(c("optparse", "data.table", "rpart"), repos="https://cloud.r-project.org")'`.
28 
29## Core Arguments
30 
31| Argument | Required | Description |
32|----------|----------|-------------|
33| `--data_file` | Yes | Input data file in CSV, TXT, or TSV format |
34| `--target_var` | Yes | Target column to predict |
35| `--task_type` | No | `auto`, `classification`, or `regression`. Default `auto` |
36| `--output_dir` | No | Output directory, default `./Decision_Tree_Results` |
37| `--train_ratio` | No | Train set ratio between 0 and 1, default `0.7` |
38| `--max_depth` | No | Maximum tree depth, default `5` |
39…