替换大 pandas 数据框中的行 [英] replace rows in a pandas data frame
问题描述
我想从一个空的数据框开始,然后每次添加一行。
我甚至可以从0数据框开始 data = pd.DataFrame(np.zeros(shape =(10,2)),column = [a,b])
,然后每次更换一行。
I want to start with an empty data frame and then add to it one row each time.
I can even start with a 0 data frame data=pd.DataFrame(np.zeros(shape=(10,2)),column=["a","b"])
and then replace one line each time.
我该怎么做?
推荐答案
$ c> .loc 用于基于标签的选择,重要的是您了解如何正确切片: http://pandas.pydata.org/pandas-docs/stable/indexing.html#selection-by-label ,并了解为什么你应该避免链接作业: http://pandas.pydata.org /pandas-docs/stable/indexing.html#indexing-view-versus-copy
Use .loc
for label based selection, it is important you understand how to slice properly: http://pandas.pydata.org/pandas-docs/stable/indexing.html#selection-by-label and understand why you should avoid chained 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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