python读写文件函数_Python文件读写功能概述,python,函数,总结

1.python读取csv文件

#!/usr/bin/python

# -*- coding: UTF-8 -*-

df = pd.read_csv(filepath,usecols=['func_name', 'para_value'])

df_t = df.fillna(value='')//对空字符进行填充

func=df_t ['func_name']//取func_name列

para=df_t ['para_value']

2.遍历路径下的文件

def file_name(file_dir):

file_list=[]

for files in os.walk(file_dir):

file_list=files[2]

return file_list

3.python从数据库中读取数据

import os

import re

import click

import numpy as np

import pandas as pd

import pymysql as psql

import datetime

import threading

time_start = (datetime.date.today()-datetime.timedelta(days=1)).strftime('%Y%m%d')

lock = threading.Lock()

def read_data_from_db(db_ip, db_port, db_user, db_pwd, db_name, sql_str):

with psql.connect(host=db_ip, port=db_port, user=db_user, passwd=db_pwd, db=db_name, charset='utf8') as conn:

lock.acquire() #获得锁定

flag = conn.execute(sql_str)

lock.release()

# 返回的是元组组成的列表

data = conn.fetchall()

return data

sql_str = “SELECT * FROM database WHERE Time >= '” + sdate + “’” + " AND " + “Time <= '” + edate + “’”+“AND Level=’”+level+"’"+“AND FileType=’”+type+ “’”

ip=“10.*.*.*”

columns_Attach = [

“Name”,

“Mail”,

“ID”,

“FileName”,

“FileType”

]

db_90 = read_data_from_db(db_ip=ip, db_port=33, db_user=“root”, db_pwd=“toor”, db_name=“DB_TEST”,sql_str=sql_str)

df_90 = pd.DataFrame(list(db_90),columns=columns_Attach)

df_data = pd.concat([df_90])

IDs = list(df_data[“ID”].values)

Mails=list(df_data[‘Mail1’])

4.python逐行写入csv

#actions是一个字典类型

DataFrame = pd.DataFrame(actions, index=[num])

if num == 0:

DataFrame.to_csv(csvName, header=True) # index=True, sep=',',

else:

DataFrame.to_csv(csvName, mode='a', header=False)

num+=1