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I formulated this question about adding rows WITH index, but it is not yet clear to me how/why this happens when there are no indexes:
columnsList=['A','B','C','D'] df8=pd.DataFrame(columns=columnsList) L=['value aa','value bb','value cc','value dd'] s = pd.Series(dict(zip(df8.columns, L))) df8.append(s,ignore_index=True) df8.append(s,ignore_index=True) I EXPECT HERE A 2X4 DATAFRAME. nevertheless no values where added, nor an error occurred.
print(df8.shape) #>>> (0,4) Why is the series not being added, and why is not given any error?
If I try to add a row with LOC, an index is added,
df8.loc[df8.index.max() + 1, :] = [4, 5, 6,7] print(df8) result:
A B C D NaN 4 5 6 7 I guess neither LOC, nor iLOC could be used to append rows without index name (i.e. Loc adds the index name NaN, and iLoc can not be used when the index number is higher than the rows of the database)
768
append was deprecated because: "Series. append and DataFrame. append [are] making an analogy to list. append, but it's a poor analogy since the behavior isn't (and can't be) in place.
Dataframe append syntax Using the append method on a dataframe is very simple. You type the name of the first dataframe, and then . append() to call the method. Then inside the parenthesis, you type the name of the second dataframe, which you want to append to the end of the first.
In pandas you can add/append a new column to the existing DataFrame using DataFrame. insert() method, this method updates the existing DataFrame with a new column. DataFrame. assign() is also used to insert a new column however, this method returns a new Dataframe after adding a new column.
DataFrame.append is not an in-place operation. From the docs,
DataFrame.append(other, ignore_index=False, verify_integrity=False, sort=None)Append rows of other to the end of this frame, returning a new object. Columns not in this frame are added as new columns.
You need to assign the result back.
df8 = df8.append([s] * 2, ignore_index=True) df8 A B C D 0 value aa value bb value cc value dd 1 value aa value bb value cc value dd If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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