Pandas:连接文件但跳过第一个文件以外的标题

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时间:2020-09-14 04:14:15  来源:igfitidea点击:

Pandas: Concatenate files but skip the headers except the first file

pythonpandas

提问by MCG Code

I have 3 files representing the same dataset split in 3 and I need to concatenate:

我有 3 个文件表示相同的数据集分成 3 个,我需要连接:

import pandas

df1 = pandas.read_csv('path1')
df2 = pandas.read_csv('path2')
df3 = pandas.read_csv('path3')

df = pandas.concat([df1,df2,df3])

But this will keep the headers in the middle of the dataset, I need to remove the headers (column names) from the 2nd and 3rd file. How do I do that?

但这会将标题保留在数据集的中间,我需要从第二个和第三个文件中删除标题(列名)。我怎么做?

采纳答案by jezrael

I think you need numpy.concatenatewith DataFrameconstructor:

我认为你需要numpy.concatenateDataFrame构造函数:

df = pd.DataFrame(np.concatenate([df1.values, df2.values, df3.values]), columns=df1.columns)

Another solution is replace columns names in df2and df3:

另一种解决方案是替换列名称中df2df3

df2.columns = df1.columns
df3.columns = df1.columns
df = pd.concat([df1,df2,df3], ignore_index=True)

Samples:

样品

np.random.seed(100)
df1 = pd.DataFrame(np.random.randint(10, size=(2,3)), columns=list('ABF'))
print (df1)
   A  B  F
0  8  8  3
1  7  7  0

df2 = pd.DataFrame(np.random.randint(10, size=(1,3)), columns=list('ERT'))
print (df2)
   E  R  T
0  4  2  5

df3 = pd.DataFrame(np.random.randint(10, size=(3,3)), columns=list('HTR'))
print (df3)
   H  T  R
0  2  2  2
1  1  0  8
2  4  0  9


print (np.concatenate([df1.values, df2.values, df3.values]))
[[8 8 3]
 [7 7 0]
 [4 2 5]
 [2 2 2]
 [1 0 8]
 [4 0 9]]

df = pd.DataFrame(np.concatenate([df1.values, df2.values, df3.values]), columns=df1.columns)
print (df)
   A  B  F
0  8  8  3
1  7  7  0
2  4  2  5
3  2  2  2
4  1  0  8
5  4  0  9


df = pd.concat([df1,df2,df3], ignore_index=True)
print (df)
   A  B  F
0  8  8  3
1  7  7  0
2  4  2  5
3  2  2  2
4  1  0  8
5  4  0  9

回答by Serenity

You have to use argument skip_rowsof read_csvfor second and third lines like here:

您必须在第二行和第三行使用参数skip_rowsread_csv如下所示:

import pandas

df1 = pandas.read_csv('path1')
df2 = pandas.read_csv('path2', skiprows=1)
df3 = pandas.read_csv('path3', skiprows=1)

df = pandas.concat([df1,df2,df3])

回答by Gustavo Bertoli

Use:

用:

df = pd.merge(df1, df2, how='outer')

Merge rows that appear in either or both df1 and df2 (union).

合并出现在 df1 和 df2(联合)中或两者中的行。