Create file_io.md

Some initial notes about interacting with files.

Author: mccright

file_io.md

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+# File Read Write  
+(*copied from https://github.com/blutterfly/python/blob/main/docs/examples/file_io.md on 2025-10-21 - thank you 'butterfly'/Larry Prestosa*)  
+
+## File IO  
+
+Quick reference and examples on writing, saving, and reading files.   
+Along with template functions for working with plain text, CSV, and JSON files.  
+
+---
+
+## 1. Plain Text File  
+
+Plain text files are the simplest type of file. You can write strings to them or read their content as text.  
+
+### Template Function for Plain Text Files  
+
+ Writing to a Plain Text File  
+
+```python
+def write_to_text_file(file_path, text):
+    with open(file_path, 'w') as file:  # Open file in write mode
+        file.write(text)  # Write text to the file
+```
+
+ Reading from a Plain Text File  
+
+```python
+def read_from_text_file(file_path):
+    with open(file_path, 'r') as file:  # Open file in read mode
+        return file.read()  # Return the content of the file
+```
+
+ Example Usage  
+
+```python
+write_to_text_file('example.txt', 'Hello, World!')
+content = read_from_text_file('example.txt')
+print(content)
+```
+
+---
+
+## 2. CSV File  
+
+CSV (Comma-Separated Values) files are used to store tabular data.  
+
+### Template Function for CSV Files  
+
+ Writing to a CSV File  
+
+```python
+import csv
+
+def write_to_csv(file_path, data):
+    with open(file_path, 'w', newline='') as file:  # Open file in write mode
+        writer = csv.writer(file)
+        writer.writerows(data)  # Write rows of data
+```
+
+ Reading from a CSV File  
+
+```python
+def read_from_csv(file_path):
+    with open(file_path, 'r') as file:  # Open file in read mode
+        reader = csv.reader(file)
+        return list(reader)  # Convert rows to a list
+```
+
+ Example Usage  
+
+```python
+data = [
+    ['Name', 'Age', 'Grade'],
+    ['Alice', 16, 'A'],
+    ['Bob', 17, 'B']
+]
+write_to_csv('students.csv', data)
+
+content = read_from_csv('students.csv')
+for row in content:
+    print(row)
+```
+
+---
+
+## 3. JSON File  
+
+JSON (JavaScript Object Notation) is used to store structured data, such as dictionaries or lists.  
+
+### Template Function for JSON Files  
+
+ Writing to a JSON File.  
+
+```python
+import json
+
+def write_to_json(file_path, data):
+    with open(file_path, 'w') as file:  # Open file in write mode
+        json.dump(data, file, indent=4)  # Write data to the file in JSON format
+```
+
+ Reading from a JSON File.  
+
+```python
+def read_from_json(file_path):
+    with open(file_path, 'r') as file:  # Open file in read mode
+        return json.load(file)  # Load data from JSON file
+```
+
+ Example Usage.  
+
+```python
+data = {
+    'students': [
+        {'name': 'Alice', 'age': 16, 'grade': 'A'},
+        {'name': 'Bob', 'age': 17, 'grade': 'B'}
+    ]
+}
+write_to_json('students.json', data)
+
+content = read_from_json('students.json')
+print(content)
+```
+
+---
+
+### Summary of File Types.  
+
+| File Type | Python Module | Best for                          |
+|-----------|---------------|------------------------------------|
+| Plain Text| `open()`       | Storing simple text or logs       |
+| CSV       | `csv`          | Tabular data                     |
+| JSON      | `json`         | Structured data (hierarchical)   |
+
+Each of these functions can be adapted based on specific requirements.  
+
+
+### Other Related Reminders:
+* Python data I/O Cheat Sheet. [https://www.fabriziomusacchio.com/.../python_data_io](https://www.fabriziomusacchio.com/teaching/python_cheat_sheets/python_data_io)  
+* Python File I/O Cheat Sheet. [https://www.cse.msu.edu/.../files-cheat-sheet.pdf](https://www.cse.msu.edu/~ldillon/cse-ctl/Spring2019/Meeting05/files-cheat-sheet.pdf)