python pandas行列合并的其他技巧mp.weixin.qq.com
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pandas中使用append方法,能够快速给dataFrame添加一些rows,或者columns。当然,效率最高的仍然是concat()方法或者merge()方法。
下面介绍一下append合并行:
append方法的官方介绍是这样的:
Append rows of
other
to the end of caller, returning a new object.
Columns in
other
that are not in the caller are added as new columns.
other : DataFrame or Series/dict-like object, or list of these The data to append.
下面举例:
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'))
>>> df
A B
0 1 2
1 3 4
>>> df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'))
# 如果直接append则index的值都不会发生变化
>>> df.append(df2)
A B
0 1 2
1 3 4
0 5 6
1 7 8
# 设置ignore_index为true
>>> df.append(df2, ignore_index=True)
A B
0 1 2
1 3 4
2 5 6
3 7 8
下面把othere设置为dict
>>> df = pd.DataFrame(columns=['A'])
>>> for i in range(5):
df = df.append({'A': i}, ignore_index=True)
>>> df
A
0 0
1 1
2 2
3 3
4 4
# More efficient(大量数据合并时,官方的推荐方式):
>>> pd.concat([pd.DataFrame([i], columns=['A']) for i in range(5)],
... ignore_index=True)
A
0 0
1 1
2 2
3 3
4 4
哈哈,以上就是python小工具关于append方法的使用的简单技巧,欢迎关注python小工具,一起学习python和pandas