How to add an extra row to a pandas dataframe
Question:
If I have an empty dataframe as such:
columns = ['Date', 'Name', 'Action','ID']
df = pd.DataFrame(columns=columns)
is there a way to append a new row to this newly created dataframe? Currently I have to create a dictionary, populate it, then append the dictionary to the dataframe at the end. Is there a more direct way?
Answers:
Upcoming pandas 0.13 version will allow to add rows through loc on non existing index data. However, be aware that under the hood, this creates a copy of the entire DataFrame so it is not an efficient operation.
Description is here and this new feature is called Setting With Enlargement.
A different approach that I found ugly compared to the classic dict+append, but that works:
df = df.T
df[0] = ['1/1/2013', 'Smith','test',123]
df = df.T
df
Out[6]:
Date Name Action ID
0 1/1/2013 Smith test 123
Try this:
df.loc[len(df)]=['8/19/2014','Jun','Fly','98765']
Warning: this method works only if there are no “holes” in the index. For example, suppose you have a dataframe with three rows, with indices 0, 1, and 3 (for example, because you deleted row number 2). Then, len(df) = 3, so by the above command does not add a new row – it overrides row number 3.
If I have an empty dataframe as such:
columns = ['Date', 'Name', 'Action','ID']
df = pd.DataFrame(columns=columns)
is there a way to append a new row to this newly created dataframe? Currently I have to create a dictionary, populate it, then append the dictionary to the dataframe at the end. Is there a more direct way?
Upcoming pandas 0.13 version will allow to add rows through loc on non existing index data. However, be aware that under the hood, this creates a copy of the entire DataFrame so it is not an efficient operation.
Description is here and this new feature is called Setting With Enlargement.
A different approach that I found ugly compared to the classic dict+append, but that works:
df = df.T
df[0] = ['1/1/2013', 'Smith','test',123]
df = df.T
df
Out[6]:
Date Name Action ID
0 1/1/2013 Smith test 123
Try this:
df.loc[len(df)]=['8/19/2014','Jun','Fly','98765']
Warning: this method works only if there are no “holes” in the index. For example, suppose you have a dataframe with three rows, with indices 0, 1, and 3 (for example, because you deleted row number 2). Then, len(df) = 3, so by the above command does not add a new row – it overrides row number 3.