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tech_docs/python/openpyxl.md

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+For working with Excel documents using Python, the `openpyxl` library is a popular choice. It allows you to read and write Excel 2010 xlsx/xlsm/xltx/xltm files, providing capabilities to create new worksheets, change cell values, apply styles, and much more. Below is a concise reference guide for common use cases with `openpyxl`, formatted in Markdown syntax:
+
+# `openpyxl` Reference Guide
+
+## Installation
+```
+pip install openpyxl
+```
+
+## Creating and Saving Workbooks
+```python
+from openpyxl import Workbook
+
+# Create a new workbook
+wb = Workbook()
+
+# Save the workbook
+wb.save('path_to_file.xlsx')
+```
+
+## Opening Existing Workbooks
+```python
+from openpyxl import load_workbook
+
+# Load an existing workbook
+wb = load_workbook('path_to_existing_file.xlsx')
+```
+
+## Working with Sheets
+```python
+# Create a new sheet
+ws1 = wb.create_sheet(title="Sheet1")
+
+# Select a sheet
+ws2 = wb["Sheet1"]
+
+# List all sheet names
+sheets = wb.sheetnames
+
+# Remove a sheet
+del wb["Sheet1"]
+```
+
+## Writing to Cells
+```python
+# Select a cell
+cell = ws1['A1']
+
+# Assign a value to the cell
+ws1['A1'] = 'Hello'
+ws1.cell(row=2, column=2, value="World")
+
+# Iterate over rows and columns
+for row in range(1, 5):
+    for col in range(1, 3):
+        ws1.cell(row=row, column=col, value=f'Row {row}, Col {col}')
+```
+
+## Reading from Cells
+```python
+# Read a cell's value
+value = ws1['A1'].value
+
+# Iterate over rows and columns
+for row in ws1.iter_rows(min_row=1, max_col=2, max_row=2):
+    for cell in row:
+        print(cell.value)
+```
+
+## Applying Styles
+```python
+from openpyxl.styles import Font, Color, Alignment, Border, Side
+
+# Create a font style
+font = Font(name='Calibri', size=12, bold=True, italic=False, color="FF0000")
+
+# Apply the font to a cell
+ws1['A1'].font = font
+
+# Create and apply border style
+border = Border(left=Side(border_style="thin", color="000000"),
+                right=Side(border_style="thin", color="000000"),
+                top=Side(border_style="thin", color="000000"),
+                bottom=Side(border_style="thin", color="000000"))
+ws1['A1'].border = border
+
+# Apply alignment
+alignment = Alignment(horizontal="center", vertical="center")
+ws1['A1'].alignment = alignment
+```
+
+## Formulas
+```python
+# Assign a formula to a cell
+ws1['A3'] = '=SUM(A1:A2)'
+```
+
+## Adding Charts
+```python
+from openpyxl.chart import BarChart, Reference
+
+# Create data for the chart
+for i in range(10):
+    ws1.append([i])
+
+# Create a bar chart
+chart = BarChart()
+data = Reference(ws1, min_col=1, min_row=1, max_col=1, max_row=10)
+chart.add_data(data, titles_from_data=True)
+
+# Add the chart to the sheet
+ws1.add_chart(chart, "E5")
+```
+
+## Working with Rows and Columns
+```python
+# Insert a row at the second position
+ws1.insert_rows(2)
+
+# Delete the third row
+ws1.delete_rows(3)
+
+# Insert a column
+ws1.insert_cols(2)
+
+# Delete a column
+ws1.delete_cols(3)
+
+# Set row height
+ws1.row_dimensions[1].height = 20
+
+# Set column width
+ws1.column_dimensions['A'].width = 30
+```
+
+## Save Changes
+```python
+wb.save('path_to_file.xlsx')
+```
+
+This guide covers the basics of creating and manipulating Excel files with `openpyxl`, including operations on workbooks and worksheets, cell manipulation, applying styles, and adding charts. These capabilities allow for robust Excel document generation and editing directly from Python scripts.