python - 从大型 CSV 中读取随机行并写入不同的 CSV 文件

Question

使用此网站，我可以从 CSV 文件中读取随机行，但是当我将这些随机行写入不同的 csv 文件时，我会丢失一些格式。这就是我的意思:

我正在读取的 csv 文件的片段:

Case,Event,P01,P02,P03,P04,P05,P06,P07,P08,P09,P10,P11,P12,P13,P14,P15,P16,P17,P18,P19,P20,P21,P22,P23,P24,P25,P26,P27,P28,P29,P30 C000167,E03468,58,10,81,-0.3406615026224174,-5.581162038780728E-4,0.650243470511574,0.9011615038586112,0.829330406449827,-0.7616995269258996,-0.0019909209274398174,-0.025834173961019672,,,,,,,,,,,,,,,,,,30, C000167,E03468,58,10,81,-0.3406615026224174,-5.581162038780728E-4,0.6517651862747824,0.9074693464398635,0.8380469158984926,-0.7589916620900861,-0.0019954144276356335,-0.03222025640621825,,,,,,,,,,,,,,,,,,30, C000167,E03468,58,10,81,-0.3468052064483135,-5.581162038780728E-4,0.6522422131598,0.9025930670926058,0.8332814044565442,-0.7508680675826261,-0.001998391716108935,-0.03533445710480293,,,,,,,,,,,,,,,,,,30,

从上面的文件中随机读取 N 行后，我得到的是:输出文件的片段:

"Case,Event,P01,P02,P03,P04,P05,P06,P07,P08,P09,P10,P11,P12,P13,P14,P15,P16,P17,P18,P19,P20,P21,P22,P23,P24,P25,P26,P27,P28,P29,P30 " "C001685,E35590,58,10,81,-0.3654481697820668,-5.581162038780728E-4,0.655619563505728,0.8856242052995037,0.7811768584356523,-0.6824944804781753,-0.0018236965581893878,0.08998255581671266,0.46818235899722466,0.5349178991074381,0.0023192678347080547,0.0023192853642003794,-1.379960600462541E-4,-0.0029589652839934494,0.0190440944409012,-0.006310411153684246,0.2667578790879315,0.8519823892954023,0.005696496533938292,0.6083983010037551,-0.15781372752517367,0.8433075356454734,0.8147766325543522,0.6320612846744368,-0.47415970209573,34,1.521461493699171 "

注意我得到的报价。当我读取输出文件时，原来的 32 列现在减少到 1 列。

我使用的代码如下:

    import random
    import csv
    import os

    os.remove("train_select.csv")

    file_size=1146880-600
    f=open("train.csv",'rb')
    dialect = csv.Sniffer().sniff(f.readline())
    f.seek(0)
    csv_file=open("train_select.csv",'wb')

    case_writer = csv.writer(csv_file,dialect)
    f.seek(0)
    random_line=f.readline()
    case_writer.writerow([random_line])

    for i in range(0,20):
      offset=random.randrange(file_size)
      f.seek(offset)
      f.readline()
      random_line=f.readline()
      case_writer.writerow([random_line])  


   f.close()
   csv_file.close()

Answer 1

由于您实际上并不关心各行的格式，因此请勿使用 csv 模块。只需将输入文件视为文本文件即可。

import random
import csv
import os

os.remove("train_select.csv")

file_size=700
f=open("train.csv",'r')
o=open("train_select.csv", 'w')

f.seek(0)
random_line=f.readline()
o.write(random_line)

for i in range(0,20):
    offset=random.randrange(file_size)
    f.seek(offset)
    f.readline()
    random_line=f.readline()
    o.write(random_line)


f.close()
o.close()