Appending to an empty DataFrame in Pandas?

Question

Is it possible to append to an empty data frame that doesn't contain any indices or columns?

I have tried to do this, but keep getting an empty dataframe at the end.

e.g.

import pandas as pd

df = pd.DataFrame()
data = ['some kind of data here' --> I have checked the type already, and it is a dataframe]
df.append(data)

The result looks like this:

Empty DataFrame
Columns: []
Index: []

Answer 1

This should work:

>>> df = pd.DataFrame()
>>> data = pd.DataFrame({"A": range(3)})
>>> df = df.append(data) 
>>> df

   A
0  0
1  1
2  2

Since the append doesn't happen in-place, so you'll have to store the output if you want it:

>>> df = pd.DataFrame()
>>> data = pd.DataFrame({"A": range(3)})
>>> df.append(data)  # without storing
>>> df
Empty DataFrame
Columns: []
Index: []
>>> df = df.append(data)
>>> df
   A
0  0
1  1
2  2

Answer 2

And if you want to add a row, you can use a dictionary:

df = pd.DataFrame()
df = df.append({'name': 'Zed', 'age': 9, 'height': 2}, ignore_index=True)

which gives you:

   age  height name
0    9       2  Zed

Answer 3

You can concat the data in this way:

InfoDF = pd.DataFrame()
tempDF = pd.DataFrame(rows,columns=['id','min_date'])

InfoDF = pd.concat([InfoDF,tempDF])

Answer 4

The answers are very useful, but since pandas.DataFrame.append was deprecated (as already mentioned by various users), and the answers using pandas.concat are not "Runnable Code Snippets" I would like to add the following snippet:

import pandas as pd

df = pd.DataFrame(columns =['name','age'])
row_to_append = pd.DataFrame([{'name':"Alice", 'age':"25"},{'name':"Bob", 'age':"32"}])
df = pd.concat([df,row_to_append])

So df is now:

    name age
0  Alice  25
1    Bob  32

Answer 5

pandas.DataFrame.append Deprecated since version 1.4.0: Use concat() instead.

Therefore:

df = pd.DataFrame() # empty dataframe
df2 = pd..DataFrame(...) # some dataframe with data

df = pd.concat([df, df2])

Answer 6

Why am I getting "AttributeError: 'DataFrame' object has no attribute 'append'?

Starting from pandas >= 2.0, append has been removed, use pd.concat instead.

The idiomatic way to append DataFrames (it to collect all your smaller DataFrames into a list, and then make one single call to pd.concat.

df_list = []
for df in some_function_that_yields_df():
    df_list.append(df)

big_df = pd.concat(df_list)

The rationale for its removal was to discourage iteratively growing DataFrames in a loop (which is what people typically use append for). This is because append makes a new copy at each stage, resulting in quadratic complexity in memory. See Creating an empty Pandas DataFrame, and then filling it (in particular, this answer) where answers discourage iteratively growing DataFrames.

More info:

• Deprecations section of version 2 release docs
• GH35407 (original deprecation proposal)