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

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)

CodePudding user response：

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.