Python: How to create a unique dataframe from multiple dataframes with the same dimensions

given an empty dataframe with assigned column names :

colnames = ('ACCT', 'CTAT', 'AAAT', 'ATCG')*3
df = pd.DataFrame(columns=colnames)

I want to loop over dataframes which have the below structure: (giving 2 for demostration)

sample_df = pd.DataFrame()
sample_df['tetran'] = colnames
sample_df['Frequency'] = (423, 512, 25, 123,632,124,614,73,14,75,311,155)
conids = ("cl1_42", "cl1_41", "cl2_31")
rep_conids = [val for val in conids for _ in range(4)]
sample_df['contig_id'] = rep_conids


sample_df_2 = pd.DataFrame()
sample_df_2['tetran'] = colnames
sample_df_2['Frequency'] = (724, 132, 4, 102,423,402,616,734,153,751,31,55)
conids_2 = ("se1_51", "se1_21", "se2_53")
rep_conids_2 = [val for val in conids_2 for _ in range(4)]
sample_df_2['contig_id'] = rep_conids_2

The objective is:

1. Add each 'Frequency' value from the 'sample_df's to the corresponding 'tetraN' value of the 'df' and add a new column to be the sample_df['contig_id']

There are multiple 'sample_df' dataframes , so this is the idea of the desired output:

I know how to do this in R but I need this to be done in python so I cannot add here what I tried due it is in R.

Thanks for your time

First, concat your dataframes then pivot them:

out = (pd.concat([sample_df, sample_df_2])
         .pivot(index='contig_id', columns='tetran', values='Frequency'))
print(out)

# Output
tetran     AAAT  ACCT  ATCG  CTAT
contig_id                        
cl1_41      614   632    73   124
cl1_42       25   423   123   512
cl2_31      311    14   155    75
se1_21      616   423   734   402
se1_51        4   724   102   132
se2_53       31   153    55   751

If you don't want the data to be sorted, use pivot_table:

out = (pd.concat([sample_df, sample_df_2])
         .pivot_table(index='contig_id', columns='tetran', values='Frequency', sort=False))
print(out)

# Output
tetran     ACCT  CTAT  AAAT  ATCG
contig_id                        
cl1_42      423   512    25   123
cl1_41      632   124   614    73
cl2_31       14    75   311   155
se1_51      724   132     4   102
se1_21      423   402   616   734
se2_53      153   751    31    55

Useful link: How can I pivot a dataframe?