如何使用 pandas 将多行转换为同一 ID 的单行

Question

我有以下格式的文本文件，它具有唯一 ID，每个唯一 ID 有四行，现在我需要将特定 ID 转换为单行。 假设如果有 8 行，output 应该有 2 行。 而且它没有 header ，我需要使用熊猫！

    xyz,name,,,12345
    2nd street,add,,,12345
    xyx@mail.com,email,,,12345
    575xxx5678,contact,,,12345

output

xyz,name,,,12345,2nd street,add,,,12345,xyx@mail.com,email,,,12345,575xxx5678,contact,,,12345

将唯一 ID 视为 12345，可以帮助我解决此问题。 那会很好。 提前致谢。

Answer 1

假设你有这个file.csv ：

www,contact,,,99999
xyz,name,,,12345
2nd street,add,,,12345
xyx@mail.com,email,,,12345
575xxx5678,contact,,,12345
qqq,contact,,,99999

要将其读取到 pandas：

df = pd.read_csv("file.csv", names=["col1", "col2", "col3", "col4", "ID"])
print(df)

印刷：

           col1     col2  col3  col4     ID
0           www  contact   NaN   NaN  99999
1           xyz     name   NaN   NaN  12345
2    2nd street      add   NaN   NaN  12345
3  xyx@mail.com    email   NaN   NaN  12345
4    575xxx5678  contact   NaN   NaN  12345
5           qqq  contact   NaN   NaN  99999

然后将其转换为您想要的 output：

x = (
    df.assign(ID2=df["ID"])
    .groupby("ID")
    .agg(list)
    .apply(lambda x: [v for l in zip(*x) for v in l], axis=1)
)

pd.DataFrame(x.tolist()).to_csv("output.txt", sep=",", header=None, index=None)

这将创建output.txt ：

xyz,name,,,12345,2nd street,add,,,12345,xyx@mail.com,email,,,12345.0,575xxx5678,contact,,,12345.0
www,contact,,,99999,qqq,contact,,,99999,,,,,,,,,,