Question

我有一张名为＆＃39; CompanyData ＆＃39;包含各种公司的数据。我需要将数据存储在与每个公司名称对应的文件中。

列是

c_emp_id, name, ph, email, company_name, country

如何使用Python解决问题

我的尝试：

import os
import pymysql

user = '***'
password = '***'
host =  '***'
db= '***'

connection = pymysql.connect(host, user, password, db)
cursor = connection.cursor()
query = "select * from CompanyData"
cursor.execute(query)
results = cursor.fetchall()
for value in results:
    filename = "{}.txt".format(value[4])
    if os.path.isfile(filename )
        fh = open(filename, 'w')
    string1 = "{}-{}-{}\n".format(value[1], value[2], value[3])
    if 'fh' in locals():
        fh.write(string1)

我在这里简化了我的问题，以便人们可以理解这个问题。

Answer 1

以下是使用pandas的解决方案。关键是按公司名称对数据进行分组，然后将每个组保存到不同的文件中。

import pandas as pd
df = pd.DataFrame({'name': ['A', 'B', 'C'], 'company': ['AAA', 'BBB', 'AAA']}) # Example of data

#       company name
# 0     AAA    A
# 1     BBB    B
# 2     AAA    C

groups = df.groupby('company')
for company, group in groups:
    group.to_csv('{0}.txt'.format(company), sep='-')

在此示例中，将创建两个文件：AAA.txt和BBB.txt。这些文件的内容将是：

-company-name
0-AAA-A
2-AAA-C

和

-company-name
1-BBB-B

为了将您的mysql数据库转换为pandas DataFrame，您可以执行以下操作：

import mysql.connector as sql
import pandas as pd

db_connection = sql.connect(host='hostname', database='db_name', user='username', password='password')
df = pd.read_sql('SELECT * FROM table_name', con=db_connection)

Answer 2

我不确定＆＃34;是否＆＃34;可以提供帮助，但我可以尝试帮助解决代码。

首先收集dict中公司的所有数据，然后执行写入，同时尝试使用＆＃34;＆＃34; ＆＃34; open＆＃34;的声明，这将处理文件的关闭。

import os
import pymysql

user = '***'
password = '***'
host =  '***'
db= '***'

connection = pymysql.connect(host, user, password, db)
cursor = connection.cursor()
query = "select * from CompanyData"
cursor.execute(query)
results = cursor.fetchall()
company_data = {}

# collect data into a dict
for value in results:
    company = value[4]
    try:
        current_data = company_data[company]
        current_data += "\n" + "-".join([value[1], value[2], value[3]])
        company_data[company] = current_data
    except KeyError:
        current_data = "-".join([value[1], value[2], value[3]])

# write the data into the file
for company, data in company_data.iteritems():
    filename = "%s.txt" % company
    with open(filename, 'w') as fh:
        fh.write(data)

保存到dict可能会创建很多中间字符串（current_data + =＆＃34; \ n＆＃34; +＆＃34; - ＆＃34; .join（[value [1]，value [2] ，价值[3]]））;不确定以下使用列表是否是更好的实现。

# collect data into a dict
for value in results:
    company = value[4]
    try:
        current_data = company_data[company]
        # since lists are mutable we do not need to re-assign this back to dict
        current_data.append("-".join([value[1], value[2], value[3]])
    except KeyError:
        current_data = "-".join([value[1], value[2], value[3]])

# write the data into the file
for company, data in company_data.iteritems():
    filename = "%s.txt" % company
    with open(filename, 'w') as fh:
        for line in data:
            fh.write(line + "\n")

如何在python中基于数据库数据创建文件？

2 个答案: