如何在 python 的 function 内的多个新创建的数据帧中返回一个非空数据帧？

Question

I am new to pandas, I have a doubt in returning a data frame from a function. I have a function which creates three new data frames based on the parameters given to it, the function has to return only the data frames which are non-empty. How do I do that?

my code:
 def df_r(df,colname,t1):
    t1_df = pd.DataFrame()
    t2_df = pd.DataFrame()
    t3_df = pd.DataFrame()
    if t1 :
      for colname in df:
           some code
           some code
           t1_df = some data
    if t2 :
      for colname in df:
           some code
           some code
           t2_df = some data
    if t3 :
      for colname in df:
           some code
           some code
           t3_df = some data
    list = [t1_df,t2_df,t3_df]

Now it should return only the t1_df as the parameter was given t1. So I have inserted all three into a list

list = [t1_df,t2_df,t3_df]

how to check if which df is non-empty and return it?

Answer 1

Just check for empty attribute for each DataFrame

eg.

df = pd.DataFrame()
if df.empty:
    print("DataFrame is empty")

output:

DataFrame is empty

pd.empty would return True if DataFrame is empty, else it would return False

This would work even if column names are present but are still missing the data.

So to answer specific to your case

list = [t1_df,t2_df,t3_df]
for df in list:
    if not df.empty:
        return df

assuming your case has only one of the DataFrame non-empty

Answer 2

if t1_df.empty != True:
        return t1_df
    elif t2_df.empty !=True:
        return t2_df
    else:
        return t2_df