YAML find and replace text Python

Question

I have some files in YAML format, I need to find the text in the $title file and replace with what I specified. What the configuration file looks like approximately:

JoinGame-MOTD:
  Enabled: true
  Messages:
  - '$title'

The YAML file may look different, so I want to make a universal code that will not get any specific string, but replace all $title with what I specified

What I was trying to do:

import sys
import yaml

with open(r'config.yml', 'w') as file:
    
    def tr(s):
        return s.replace('$title', 'Test')

        yaml.dump(file, sys.stdout, transform=tr)

Please help me. It is not necessary to work with my code, I will be happy with any examples that can suit me

So, how is your code working for you? Is there anything you need to improve? — quamrana, Jan 14 '21 at 14:25
take a look at [this question](https://stackoverflow.com/questions/61228863/transform-attribute-in-yaml-dump-is-not-working), maybe its answers may help — Rafael de Bem, Jan 14 '21 at 14:28
Do you get any errors? If so, could you let us know which ones? — Axiumin_, Jan 14 '21 at 14:35
@Axiumin_ no, but the file becomes completely empty after that — DorgZ, Jan 14 '21 at 14:38

pistolpete · Accepted Answer · 2021-01-14T14:52:42.920

2

Might be easier to not use the yaml package at all.

with open("file.yml", "r") as fin:
     with open("file_replaced.yml", "w") as fout:
         for line in fin:
             fout.write(line.replace('$title', 'Test'))

EDIT:

To update in place

with open("config.yml", "r+") as f:
    contents = f.read()
    f.seek(0)
    f.write(contents.replace('$title', 'Test'))
    f.truncate()

edited Jan 14 '21 at 14:52

answered Jan 14 '21 at 14:44

pistolpete

968
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20

It works, thank you. Is it possible to make changes in the file and save them to the same one, so as not to create a copy? – DorgZ Jan 14 '21 at 14:49
Edited to write in place – pistolpete Jan 14 '21 at 14:53

score 0 · Answer 2 · answered Jan 14 '21 at 14:51

You can also read & write data in one go. os.path.join is optional, it makes sure the yaml file is read relative to path your script is stored

import re
import os

with open(os.path.join(os.path.dirname(__file__), 'temp.yaml'), 'r+') as f:
    data = f.read()
    f.seek(0)
    new_data = data.replace('$title', 'replaced!')
    f.write(new_data)
    f.truncate()

In case you wish to dynamically replace other keywords besides $title, like $description or $name, you can write a function using regex like this;

def replaceString(text_to_search, keyword, replacement):
    return re.sub(f"(\${keyword})[\W]", replacement, text_to_search)

replaceString('My name is $name', '$name', 'Bob')

YAML find and replace text Python

2 Answers2