R中如何将分类变量抽取出来？

lujincao314159

columnA columnB
1 beijing 0.5454
2 beijing;shanghai 0.3536
3 guangzhou;tianjing;zhenzhou 0.5250

每个单元格使用；分开的变成

columnA columnB
1 beijing 0.5454
2 beijing; 0.3536
3 shanghai 0.3536
4 guangzhou 0.5250
5 tianjing 0.5250
6 zhenzhou 0.5250

lujincao314159

csv某一列的每个单元格里有多个分类变量，而且是用“；”隔开的。
如何把每个变量提取出来自成一行，其对应那一行的其他数据跟着重复？
忘不吝赐教

enthumelon

Python 写着玩（假设你那个第一列的什么1 2 3 4没有的话）。

import pandas as pd


def readCos410531(filename):
    """COS 410531
    """

    res = {}
    with open(filename, "r") as text:
        next(text)
        ii = 0
        for line in text:
            value, key = line.split()
            value = value.split(";")
            for i in value:
                res[ii] = [key, i]
                ii = ii+1
    re = pd.DataFrame.from_dict(res).transpose()
    re.columns = ["Value", "City"]
    return re


# Example
filename = "cos410531.txt"
re = readCos410531(filename)

enthumelon

[未知用户]

想起来坛子里用正则的人不少，下面的也可以哦(shell下):

gawk '{x=gensub(";","\t"$2"\n","g",$1); print x "\t" $2}' cos410531.txt

结果如下

$ cat cos410531.txt
columnA columnB
beijing 0.5454
beijing;shanghai        0.3536
guangzhou;tianjing;zhenzhou     0.5250
$ gawk '{x=gensub(";","\t"$2"\n","g",$1); print x "\t" $2}' cos410531.txt
columnA columnB
beijing 0.5454
beijing 0.3536
shanghai        0.3536
guangzhou       0.5250
tianjing        0.5250
zhenzhou        0.5250

lujincao314159

[未知用户]
多谢啦