to_string(index = False) results in non empty string even when dataframe is empty

Question

I am doing the following in my python script and I want to hide the index column when I print the dataframe. So I used .to_string(index = False) and then use len() to see if its zero or not. However, when i do to_string(), if the dataframe is empty the len() doesn't return zero. If i print the procinject1 it says "Empty DataFrame". Any help to fix this would be greatly appreciated.

procinject1=dfmalfind[dfmalfind["Hexdump"].str.contains("MZ") == True].to_string(index = False)
if len(procinject1) == 0:
    print(Fore.GREEN + "[✓]No MZ header detected in malfind preview output")
else:
    print(Fore.RED + "[!]MZ header detected within malfind preview (Process Injection indicator)")
    print(procinject1)

Answer 1

That's the expected behaviour in Pandas DataFrame.

In your case, procinject1 stores the string representation of the dataframe, which is non-empty even if the corresponding dataframe is empty.

For example, check the below code snippet, where I create an empty dataframe df and check it's string representation:

df = pd.DataFrame()
print(df.to_string(index = False)) 
print(df.to_string(index = True))

For both index = False and index = True cases, the output will be the same, which is given below (and that is the expected behaviour). So your corresponding len() will always return non-zero.

Empty DataFrame
Columns: []
Index: []

But if you use a non-empty dataframe, then the outputs for index = False and index = True cases will be different as given below:

data = [{'A': 10, 'B': 20, 'C':30}, {'A':5, 'B': 10, 'C': 15}]
df = pd.DataFrame(data)
print(df.to_string(index = False)) 
print(df.to_string(index = True))

Then the outputs for index = False and index = True cases respectively will be -

A  B  C
10 20 30
5 10 15

    A   B   C
0  10  20  30
1   5  10  15

Since pandas handles empty dataframes differently, to solve your problem, you should first check whether your dataframe is empty or not, using pandas.DataFrame.empty.

Then if the dataframe is actually non-empty, you could print the string representation of that dataframe, while keeping index = False to hide the index column.