Modify date format in all existing docs

Questions & Help
1

So I recently changed date format in the setting, and re-indexed the graph. But I noticed that in all old entries, my journal link is still in the old format ( [[Dec. 31st, 2024]] and not the new format [[2024_12_31]].

Is there a way to batch modify all my [[MMM. Do, YYYY]] to the new format?

2

Only through scripting, probably utilizing regular expressions. Should then re-index once more.

3

I have asked chatgpt to help. THis is what it output. Would you mind quickly see if anything should be amended?

import os
import re
from datetime import datetime

# Define the function to convert the date format
def convert_date_format(match):
    # Extract the date (e.g., 'Jan 2nd, 2025')
    date_str = match.group(1)
    
    # Remove suffixes like 'st', 'nd', 'rd', 'th' from the day part
    date_str = re.sub(r'(\d+)(st|nd|rd|th)', r'\1', date_str)
    
    # Parse the date into a datetime object (this will handle the comma)
    try:
        date_obj = datetime.strptime(date_str, '%b %d, %Y')
        
        # Return the new format
        return f"[[{date_obj.strftime('%Y_%m_%d')}]"
    except ValueError:
        # If there is an issue parsing the date, return the original match
        return match.group(0)

# Directory containing the .md files
md_files_directory = "/path/to/your/markdown/files"

# Regular expression to find the dates in the old format
date_pattern = r'\[\[([A-Za-z]{3} \d{1,2}(?:st|nd|rd|th)?\, \d{4})\]\]'

# Walk through all files in the directory
for root, dirs, files in os.walk(md_files_directory):
    for file in files:
        if file.endswith(".md"):
            file_path = os.path.join(root, file)
            
            # Read the content of the markdown file
            with open(file_path, 'r', encoding='utf-8') as f:
                content = f.read()
            
            # Replace the old date format with the new one
            new_content = re.sub(date_pattern, convert_date_format, content)
            
            # If the content was modified, write the new content back to the file
            if new_content != content:
                with open(file_path, 'w', encoding='utf-8') as f:
                    f.write(new_content)
                print(f"Updated: {file_path}")

I would definitely back up before this.

4

I tried-and-errored the pytho. Below script works for me and I have successfully updated the graph. ps. I did not check all docs, but for the docs I sampled, nothing is changed except for the date format (which is the goal).

Update the .py for everyone here.
Note

  1. update the graph path below.
  2. my date format is from [[MMM Do, yyyy]] to [[yyyy_MM_DD]]. if your old entries uses different format, you need to ask chatgpt to change the code
  3. it created a update log in the folder of where your .py is stored.
import os
import re
from datetime import datetime

# Define the function to convert the date format
def convert_date_format(match):
    # Extract the date (e.g., 'Jan 2nd, 2025')
    date_str = match.group(1)
    
    # Remove suffixes like 'st', 'nd', 'rd', 'th' from the day part
    date_str = re.sub(r'(\d+)(st|nd|rd|th)', r'\1', date_str)
    
    # Ensure the date has no leading zeros in day and month
    date_str = re.sub(r'\b0(\d)', r'\1', date_str)
    
    # Parse the date into a datetime object (this will handle the comma)
    try:
        date_obj = datetime.strptime(date_str, '%b %d, %Y')
        
        # Return the new format
        return f"[[{date_obj.strftime('%Y_%m_%d')}]]"
    except ValueError:
        # If there is an issue parsing the date, return the original match
        return match.group(0)
    
# Directory containing the .md files
md_files_directory = "C:/Users/XXX/YYY/OOO"

# Regular expression to find the dates in the old format
date_pattern = r'\[\[([A-Za-z]{3} \d{1,2}(?:st|nd|rd|th)?\, \d{4})\]\]'

# Open a log file to record updates
with open("update_log.txt", "w", encoding="utf-8") as log_file:
    # Walk through all files in the directory
    for root, dirs, files in os.walk(md_files_directory):
        for file in files:
            if file.endswith(".md"):
                file_path = os.path.join(root, file)
                
                # Read the content of the markdown file
                with open(file_path, 'r', encoding='utf-8') as f:
                    content = f.read()
                
                # Replace the old date format with the new one
                new_content = re.sub(date_pattern, convert_date_format, content)
                
                # If the content was modified, write the new content back to the file
                if new_content != content:
                    with open(file_path, 'w', encoding='utf-8') as f:
                        f.write(new_content)
                    
                    # Log the update to the log file
                    log_file.write(f"Updated: {file_path}\n")

print("Date updates have been logged to 'update_log.txt'.")