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Replace rows in pandas data frame

I want to start with an empty data frame, and then add one row to it every time. I can even start with data frame 0 data=pd.DataFrame(np.zeros(shape=(10,2)),column=["a","b"]), and then replace one line each time.

How can i do this?

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1 answer

Use .locfor selection based on labels, it is important to understand how to cut correctly: http://pandas.pydata.org/pandas-docs/stable/indexing.html#selection-by-label and understand why you should avoid the associated assignment: http : //pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy

In [14]:

data=pd.DataFrame(np.zeros(shape=(10,2)),columns=["a","b"])
data
Out[14]:
   a  b
0  0  0
1  0  0
2  0  0
3  0  0
4  0  0
5  0  0
6  0  0
7  0  0
8  0  0
9  0  0

[10 rows x 2 columns]
In [15]:

data.loc[2:2,'a':'b']=5,6
data
Out[15]:
   a  b
0  0  0
1  0  0
2  5  6
3  0  0
4  0  0
5  0  0
6  0  0
7  0  0
8  0  0
9  0  0

[10 rows x 2 columns]
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