在Python中使用petl package将数据导出到文本文件

Question

我试图从文本文件中提取原始数据，在处理完原始数据后，我想将其导出到另一个文本文件中。下面是我为这个过程编写的python代码。为此，我使用了python3中的“petl”包位置.txt'是原始数据文件。在

import glob, os
from petl import *


class ETL():

    def __init__(self, input):
        self.list = input


    def parse_P(self):
        personids = None
        for term in self.list:
            if term.startswith('P'):
                personids = term[1:]
        personid = personids.split(',')

        return personid

    def return_location(self):
        location = None
        for term in self.list:
            if term.startswith('L'):
                location = term[1:]
        return location

    def return_location_id(self, location):
        location = self.return_location()
        locationid = None


    def return_country_id(self):
        countryid = None
        for term in self.list:
            if term.startswith('C'):
                countryid = term[1:]

        return countryid

    def return_region_id(self):
        regionid = None
        for term in self.list:
            if term.startswith('R'):
                regionid = term[1:]

        return regionid

    def return_city_id(self):
        cityid = None
        for term in self.list:
            if term.startswith('I'):
                cityid = term[1:]
        return cityid

print (os.getcwd())
os.chdir("D:\ETL-IntroductionProject")
print (os.getcwd())
final_location = [['L','P', 'C', 'R', 'I']]

new_location = fromtext('locations.txt', encoding= 'Latin-1')
stored_list = [] 
for identifier in new_location:
    if identifier[0].startswith('L'):
        identifier = identifier[0]
        info_list = identifier.split('_')
        stored_list.append(info_list)

for lst in stored_list:
    tabling = ETL(lst)
    location = tabling.return_location()
    country = tabling.return_country_id()
    city = tabling.return_city_id()
    region = tabling.return_region_id()
    person_list = tabling.parse_P()
    for person in person_list:
        table_new = [location, person, country, region, city]
        final_location.append(table_new)

totext(final_location, 'l1.txt')

然而，当我使用petl的“totext”函数时，它会抛出一个“断言错误”。在

AssertionError: template is required I am unable to understand what the fault is. Can some one please explain the problem I am facing and what I should be doing ?

Answer 1

toext函数的template参数不是可选的没有关于如何写入行的默认格式在这种情况下，必须提供一个模板。在这里查看文档以获取下一个示例：https://petl.readthedocs.io/en/latest/io.html#text-files

模板描述了它使用字段头来描述事情的每一行的格式，您也可以选择传入序言来编写标题。在您的案例中，基本模板是：

table_new_template = "{L} {P} {C} {R} {I}" totext(final_location, 'l1.txt', template=table_new_template)