Insert conditional values into dict from key using RE

Question

So my problem is quite simple, my conditions are:

1. if "__" in key, insert 'class=\"\" ' into opening tag in value pair: <tag></tag> so it becomes: <tag class=""></tag> then insert the relevant values of "__"
2. else leave <tag></tag> as is

I've done 95% of this but I'm missing one step. Here is my dict and code:

d1 = {
  "h1": "<h1 class=\"my-heading\">[]</h1>",
  "h1__display-3": "<h1 class=\" \">[]</h1>",
  "h1__display-3_text-white_text-center": "<h1 class=\" \">[]</h1>",
  "h1__mt-4": "<h1 class=\"\">[]</h1>",
  "h1__mt-5": "<h1 class=\" \">[]</h1>",
  "h1__mt-5_kakabum": "<h1 class=\" \">[]</h1>",
  "h1__my-4": "<h1 class=\" \">[]</h1>",
  "h2": "<h2>[]</h2>",
  "h2__card-title": "<h2 class=\"\">[]</h2>",
  "h2__mt-4": "<h2 class=\"\">[]</h2>",
  "h2__my-4": "<h2 class=\"\">[]</h2>"
}

d2 = {k:k for k, v in d1.items()}
res = {}
for k in d2:
    key = k.split('__')[0]
    if key in d1:
        res[k] = d1[key]
        res2 = {k: re.sub(r'class="([\w\- ]+)"', r'class="\1 ' + d2[k] + '"', v) for k,v in res.items()}
        res3 = {k: re.sub(r'\w\w\__', r'', v).replace('_', ' ') for k, v in res2.items()}

print('Res', json.dumps(res3, indent= 2))

After above I get undesired:

 {
  "h1": "<h1 class=\"my-heading h1\">[]</h1>", # notice the unnecessary 'h1' in class
  "h1__display-3": "<h1 class=\"my-heading display-3\">[]</h1>",
  "h1__display-3_text-white_text-center": "<h1 class=\"my-heading display-3 text-white text-center\">[]</h1>",
  "h1__mt-4": "<h1 class=\"my-heading mt-4\">[]</h1>",
  "h1__mt-5": "<h1 class=\"my-heading mt-5\">[]</h1>",
  "h1__mt-5_kakabum": "<h1 class=\"my-heading mt-5 kakabum\">[]</h1>",
  "h1__my-4": "<h1 class=\"my-heading my-4\">[]</h1>",
  "h2": "<h2>[]</h2>",
  "h2__card-title": "<h2>[]</h2>",
  "h2__mt-4": "<h2>[]</h2>",
  "h2__my-4": "<h2>[]</h2>"
}

Instead of desired:

 {
  "h1": "<h1 class=\"my-heading\">[]</h1>", 
  "h1__display-3": "<h1 class=\"my-heading display-3\">[]</h1>",
  "h1__display-3_text-white_text-center": "<h1 class=\"my-heading display-3 text-white text-center\">[]</h1>",
  "h1__mt-4": "<h1 class=\"my-heading mt-4\">[]</h1>",
  "h1__mt-5": "<h1 class=\"my-heading mt-5\">[]</h1>",
  "h1__mt-5_kakabum": "<h1 class=\"my-heading mt-5 kakabum\">[]</h1>",
  "h1__my-4": "<h1 class=\"my-heading my-4\">[]</h1>",
  "h2": "<h2>[]</h2>", 
  "h2__card-title": "<h2 class=\"card-title\">[]</h2>", 
  "h2__mt-4": "<h2 class=\"mt-4\">[]</h2>",
  "h2__my-4": "<h2 class=\"my-4\">[]</h2>"
}

^notice: No class attribute as per d1 for "h2": "<h2>[]</h2>", but because key has '__', class pattern has been inserted "h2__card-title": "<h2 class=\"card-title\">[]</h2>".

I'm missing the step between res2 and res3, could someone help me out?

Answer 1

Ok I solved it by reading the python regex documentation in detail, was my weakness: https://docs.python.org/3.3/howto/regex.html

The solution is below (using same dict as OP):

d2 = {k:k for k, v in d1.items()}
mydict = {}
for k in d2:
    key = k.split('__')[0]
    if key in d1:
        mydict[k] = d1[key]
        # @params: re.sub(pattern, repl, string, max=0)
        class_regex = r'class="([\w\- ]+)"'
        underscore_regex = '\w+(__{1,2})'
        arrow_regex = '\w+(>+)'

        res2 = {k: re.sub(class_regex, r'class="\1 ' + (k if re.search(re.compile(underscore_regex), k) else '') + '"', v) for k,v in mydict.items()}
        res3 = {k: (v if re.search(re.compile(underscore_regex), v) else (v if re.search(re.compile(class_regex), v) else re.sub(r'(>)', r' class="' + (k if re.search(re.compile(underscore_regex), k) else re.sub(class_regex, r'', '')) + '">', v, 1))) for k, v in res2.items()}
        res4 = {k: re.sub(r'__', r' ', v).replace('_', ' ') for k, v in res3.items()}
        res5 = {k: re.sub(r' class=\"\"', r'', v) for k, v in res4.items()}

print(json.dumps(res5, indent= 2, sort_keys=True))

Which results in the correct output:

 {
  "h1": "<h1 class=\"my-heading\">[]</h1>", 
  "h1__display-3": "<h1 class=\"my-heading display-3\">[]</h1>",
  "h1__display-3_text-white_text-center": "<h1 class=\"my-heading display-3 text-white text-center\">[]</h1>",
  "h1__mt-4": "<h1 class=\"my-heading mt-4\">[]</h1>",
  "h1__mt-5": "<h1 class=\"my-heading mt-5\">[]</h1>",
  "h1__mt-5_kakabum": "<h1 class=\"my-heading mt-5 kakabum\">[]</h1>",
  "h1__my-4": "<h1 class=\"my-heading my-4\">[]</h1>",
  "h2": "<h2>[]</h2>", 
  "h2__card-title": "<h2 class=\"card-title\">[]</h2>", 
  "h2__mt-4": "<h2 class=\"mt-4\">[]</h2>",
  "h2__my-4": "<h2 class=\"my-4\">[]</h2>"
}