在 Python 中拆分数据框列

Question

我正在尝试从 Pandas Dataframe df删除一些行。 它看起来像这样，有 180 行和 2745 列。 我想摆脱那些有行curv_typ的PYC_RT和YCIF_RT 。 我也想摆脱geo\\time列。 我正在从 CSV 文件中提取此数据，并且必须意识到curv_typ,maturity,bonds,geo\\time及其下方的字符（如PYC_RT,Y1,GBAAA,EA都在一个列中：

 curv_typ,maturity,bonds,geo\time  2015M06D16   2015M06D15   2015M06D11   \
0                 PYC_RT,Y1,GBAAA,EA        -0.24        -0.24        -0.24   
1               PYC_RT,Y1,GBA_AAA,EA        -0.02        -0.03        -0.10   
2                PYC_RT,Y10,GBAAA,EA         0.94         0.92         0.99   
3              PYC_RT,Y10,GBA_AAA,EA         1.67         1.70         1.60   
4                PYC_RT,Y11,GBAAA,EA         1.03         1.01         1.09 

我决定尝试拆分此列，然后删除生成的单个列，但在代码的最后一行出现错误KeyError: 'curv_typ,maturity,bonds,geo\\time' df_new = pd.DataFrame(df['curv_typ,maturity,bonds,geo\\time'].str.split(',').tolist(), df[1:]).stack()

import os
import urllib2
import gzip
import StringIO
import pandas as pd

baseURL = "http://ec.europa.eu/eurostat/estat-navtree-portlet-prod/BulkDownloadListing?file="
filename = "data/irt_euryld_d.tsv.gz"
outFilePath = filename.split('/')[1][:-3]

response = urllib2.urlopen(baseURL + filename)
compressedFile = StringIO.StringIO()
compressedFile.write(response.read())

compressedFile.seek(0)

decompressedFile = gzip.GzipFile(fileobj=compressedFile, mode='rb') 

with open(outFilePath, 'w') as outfile:
    outfile.write(decompressedFile.read())

#Now have to deal with tsv file
import csv

with open(outFilePath,'rb') as tsvin, open('ECB.csv', 'wb') as csvout:
    tsvin = csv.reader(tsvin, delimiter='\t')
    writer = csv.writer(csvout)
    for data in tsvin:
        writer.writerow(data)


csvout = 'C:\Users\Sidney\ECB.csv'
#df = pd.DataFrame.from_csv(csvout)
df = pd.read_csv('C:\Users\Sidney\ECB.csv', delimiter=',', encoding="utf-8-sig")
print df
df_new = pd.DataFrame(df['curv_typ,maturity,bonds,geo\time'].str.split(',').tolist(), df[1:]).stack()

编辑：从 reptilicus 的回答中，我使用了以下代码：

#Now have to deal with tsv file
import csv

outFilePath = filename.split('/')[1][:-3] #As in the code above, just put here for reference
csvout = 'C:\Users\Sidney\ECB.tsv'
outfile = open(csvout, "w")
with open(outFilePath, "rb") as f:
    for line in f.read():
        line.replace(",", "\t")
        outfile.write(line)
outfile.close()

df = pd.DataFrame.from_csv("ECB.tsv", sep="\t", index_col=False)

我仍然得到与以前相同的确切输出。

谢谢你

Answer 1

那个 CSV 的格式很糟糕，里面有逗号和制表符分隔的数据。

先去掉逗号：

tr ',' '\t' < irt_euryld_d.tsv > test.tsv

如果你不能使用tr可以在 python 中做到：

outfile = open("outfile.tsv", "w")
with open("irt_euryld_d.tsz", "rb") as f:
    for line in f.read():
        line.replace(",", "\t")
        outfile.write(line)
outfile.close()

然后可以在熊猫中很好地加载它：

In [9]: df = DataFrame.from_csv("test.tsv", sep="\t", index_col=False)

In [10]: df
Out[10]:
    curv_typ maturity    bonds geo\time  2015M06D17   2015M06D16   \
0     PYC_RT       Y1    GBAAA       EA        -0.23        -0.24
1     PYC_RT       Y1  GBA_AAA       EA        -0.05        -0.02
2     PYC_RT      Y10    GBAAA       EA         0.94         0.94
3     PYC_RT      Y10  GBA_AAA       EA         1.66         1.67
In [11]: df[df["curv_typ"] != "PYC_RT"]
Out[11]:
    curv_typ maturity    bonds geo\time  2015M06D17   2015M06D16   \
60   YCIF_RT       Y1    GBAAA       EA        -0.22        -0.23
61   YCIF_RT       Y1  GBA_AAA       EA         0.04         0.08
62   YCIF_RT      Y10    GBAAA       EA         2.00         1.97