How to append dictionary rows into empty pandas dataframe?

Question

I have a dataframe df and and empty dataframes df1 and df2. I am trying to append rows if conditions are true in df1 or df2


##df is my input dataframe

#df1 and df2 are empty dataframe
df1 = pd.DataFrame(columns = df.columns)
df2 = pd.DataFrame(columns = df.columns)


df_dict = df.to_dict('records')
for rows in df_dict:
     if condition1 == true:
       print(rows)
       df1.append(rows, ignore_index = True)

     else:
       print(rows)
       df2.append(rows, ignore_index = True)

print is returning rows but append is empty

PTQuoc · Accepted Answer · 2022-07-22 04:32:07Z

1

Don't use append cuz it is depreciated. Instead use concat will solve your problem. Also, you do not need to iterate by row

However, I see your problem is not that complicated. It is simply using .loc:

df1 = df.loc[df['col'] == condition, : ].copy()
df2 = df.loc[~(df['col'] == condition), : ].copy()

If df1 and df2 is not empty dataframe, and you want to add rows meeting condition to them:

tem1 = df.loc[df['col'] == condition, : ].copy()
tem2 = df.loc[~(df['col'] == condition), : ].copy()

# df1:
df1 = pd.concat([df1, tem1])

# df2:
df2 = pd.concat([df2, tem2])

answered Jul 22, 2022 at 4:32

PTQuoc

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2 Comments

Shubh Over a year ago

if condition: append into df1, else append into df2 . This requires looping through ?

PTQuoc Over a year ago

@Shubh: from your code, I understand that I can divide df into two groups. Group of rows that meet condition, call gr A, and group of rows not meet condition, call gr B. Instead of iterating each row (which takes a lot of time), you can use .loc to filter those rows that belong to group A (meet condition) as df1 and group B (not meet condition) as `df2'. If I miss understand your question, please elaborate it a bit more.

AnhPC03 · Accepted Answer · 2022-07-22 04:31:19Z

0

You need to assign df1 and df2 again for it works, else the value of df1 and df2 will not be updated. Beside, you it must be df1.append, not df1.appned

##df is my input dataframe

#df1 and df2 are empty dataframe
df1 = pd.DataFrame(columns = df.columns)
df2 = pd.DataFrame(columns = df.columns)


df_dict = df.to_dict('records')
for row in df_dict:
    if conditions1 == true:
        print(row)
        df1 = df1.append(row, ignore_index = True)
    else:
        print(row)
        df2 = df2.append(row, ignore_index = True)

print(df1)

answered Jul 22, 2022 at 4:31

AnhPC03

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2 Comments

Shubh Over a year ago

obviously it was Typo

AnhPC03 Over a year ago

@Shubh it was typo, but you really need to assign df1 again

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