TypeError: string indices must be integers - But I'm using floats?

Question

I want to highlight the row if the credits in df equal the debits df_cb.

My previous code is just filling in the NaNs with 0.

df = df.fillna(0)
df[['Debits (£)', 'Credit(£)']]  = df[['Debits (£)', 
'Credit(£)']].replace(',','',regex=True).astype(float)
df_cb = df_cb.fillna(0)
df_cb[['Debits (£)', 'Credit(£)']]  = df_cb[['Debits (£)', 
'Credit(£)']].replace(',','',regex=True).astype(float)

df

df_cb

I've applied the following code:

df.style.apply(lambda x: (["background: yellow" if (df['Credit(£)'].equals(df_cb['Debits (£)']))else "" for df in df_cb]), axis = 1)<

 df_cb.style.apply(lambda x: (["background: yellow" if (df['Credit(£)'].equals(df_cb['Debits (£)'])) else "" for df_cb in df]), axis = 1)

However, I receive this error:

TypeError: string indices must be integers

I am definitely not using strings, I've assigned the values to be floats as they're decimals.

So why is telling me they need to be integers for an if statement?

Many thanks,

[EDIT - Full Traceback below]:

   --------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/IPython/core/formatters.py in __call__(self, obj)
   343             method = get_real_method(obj, self.print_method)
   344             if method is not None:
--> 345                 return method()
   346             return None
   347         else:

/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/io/formats/style.py in _repr_html_(self)
   270         """
   271         if get_option("styler.render.repr") == "html":
--> 272             return self.to_html()
   273         return None
   274 

/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/io/formats/style.py in to_html(self, buf, table_uuid, table_attributes, sparse_index, sparse_columns, bold_headers, caption, max_rows, max_columns, encoding, doctype_html, exclude_styles, **kwargs)
  1176         encoding = encoding or get_option("styler.render.encoding")
  1177         # Build HTML string..
-> 1178         html = obj._render_html(
  1179             sparse_index=sparse_index,
  1180             sparse_columns=sparse_columns,

/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/io/formats/style_render.py in _render_html(self, sparse_index, sparse_columns, max_rows, max_cols, **kwargs)
   155         Generates a dict with necessary kwargs passed to jinja2 template.
   156         """
--> 157         self._compute()
   158         # TODO: namespace all the pandas keys
   159         d = self._translate(sparse_index, sparse_columns, max_rows, max_cols)

/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/io/formats/style_render.py in _compute(self)
   198         r = self
   199         for func, args, kwargs in self._todo:
--> 200             r = func(self)(*args, **kwargs)
   201         return r
   202 

/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/io/formats/style.py in _apply(self, func, axis, subset, **kwargs)
  1441                 result = data.apply(func, axis=0, **kwargs)
  1442             else:
-> 1443                 result = data.T.apply(func, axis=0, **kwargs).T  # see GH 42005
  1444 
  1445         if isinstance(result, Series):

/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/core/frame.py in apply(self, func, axis, raw, result_type, args, **kwargs)
  8831             kwargs=kwargs,
  8832         )
-> 8833         return op.apply().__finalize__(self, method="apply")
  8834 
  8835     def applymap(

/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/core/apply.py in apply(self)
   725             return self.apply_raw()
   726 
--> 727         return self.apply_standard()
   728 
   729     def agg(self):

/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/core/apply.py in apply_standard(self)
   849 
   850     def apply_standard(self):
--> 851         results, res_index = self.apply_series_generator()
   852 
   853         # wrap results

/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/pandas/core/apply.py in apply_series_generator(self)
   865             for i, v in enumerate(series_gen):
   866                 # ignore SettingWithCopy here in case the user mutates
--> 867                 results[i] = self.f(v)
   868                 if isinstance(results[i], ABCSeries):
   869                     # If we have a view on v, we need to make a copy because

/var/folders/63/d4r2059n7z5_v4vbtw244jp00000gp/T/ipykernel_10032/2672574164.py in <lambda>(x)
     1 df.style.apply(lambda x: (["background: yellow" if (df['Credit(£)'] == (df_cb['Debits (£)']))else "" for df in df_cb]), axis = 1)
----> 2 df_cb.style.apply(lambda x: (["background: yellow" if (df['Credit(£)']==(df_cb['Debits (£)'])) else "" for df_cb in df]), axis = 1)

/var/folders/63/d4r2059n7z5_v4vbtw244jp00000gp/T/ipykernel_10032/2672574164.py in <listcomp>(.0)
     1 df.style.apply(lambda x: (["background: yellow" if (df['Credit(£)'] == (df_cb['Debits (£)']))else "" for df in df_cb]), axis = 1)
----> 2 df_cb.style.apply(lambda x: (["background: yellow" if (df['Credit(£)']==(df_cb['Debits (£)'])) else "" for df_cb in df]), axis = 1)

TypeError: string indices must be integers

<pandas.io.formats.style.Styler at 0x10ecaf5e0> ```