Python读写文件的几种方式

一、pandas

pandas模块是数据分析的大杀器，它使得对于文件相关的操作变得简单。

看一下它的简单使用

import pandas as pd

# 读取
df = pd.read_csv('all_forum_info.csv')
print(df.info())

# 写入
df.to_csv('data.csv')

具体用法参照我的博客pandas系列 https://www.cnblogs.com/zhangyafei/p/10685438.html

二、csv

1.读取

import csv

# 读取
with open('all_forum_info.csv', encoding='utf-8') as myFile:
    lines = csv.reader(myFile)
    for line in lines:
        print(line)

['hgroup', 'forum_topic', 'forum_url', 'count_topic', 'count_post']
['Welcome to Breastcancer.org', 'Info & Resources for New Patients & Members - Please No Posts!', 'https://community.breastcancer.org/forum/131', '11', '11']
['Welcome to Breastcancer.org', 'Acknowledging and honoring our Community', 'https://community.breastcancer.org/forum/135', '111', '5,372']
['Not Diagnosed but Concerned', 'Not Diagnosed But Worried', 'https://community.breastcancer.org/forum/83', '16,638', '133,217']
['Not Diagnosed but Concerned', 'Waiting for Test Results', 'https://community.breastcancer.org/forum/62', '6,712', '62,439']
['Not Diagnosed but Concerned', 'Benign Breast Conditions', 'https://community.breastcancer.org/forum/148', '795', '4,094']
['Not Diagnosed but Concerned', 'High Risk for Breast Cancer', 'https://community.breastcancer.org/forum/47', '2,146', '23,435']
['Tests, Treatments & Side Effects', 'Just Diagnosed', 'https://community.breastcancer.org/forum/5', '6,894', '103,851']
['Tests, Treatments & Side Effects', 'Diagnosed and Waiting for Test Results', 'https://community.breastcancer.org/forum/147', '592', '6,442']

2. 写入

"""
写入
'w'表示写模式。
首先open()函数打开当前路径下的名字为't.csv'的文件，如果不存在这个文件，则创建它，返回myFile文件对象。
csv.writer(myFile)返回writer对象myWriter。
writerow()方法是一行一行写入，writerows方法是一次写入多行。
注意：如果文件't.csv'事先存在，调用writer函数会先清空原文件中的文本，再执行writerow/writerows方法。
"""

with open('data.csv', 'w', encoding='utf-8') as myFile:
    myWriter = csv.writer(myFile)
    myWriter.writerow(['title', '数学'])
    myWriter.writerow([8, 'h'])
    myList = [[1, 2, 3], [4, 5, 6]]
    myWriter.writerows(myList)

data.csv

title,数学
8,h
1,2,3
4,5,6

修改分割符

csv.register_dialect('mydialect', delimiter='|', quoting=csv.QUOTE_ALL)
with open('test.csv', 'r') as myFile:
    lines = csv.reader(myFile, 'mydialect')
    # print(lines.line_num)
    for line in lines:
        print(line)

['1', '2', '3']
['2', '3', '4']　　

三、xlrd, xlwt

1. 读取

import xlrd

myWorkbook = xlrd.open_workbook('data.xlsx')

# 读取excel的三种方式

# 方式一
mySheets = myWorkbook.sheets()  # 获取工作表list。
mySheet = mySheets[0]  # 通过索引顺序获取。
# 方式二
# mySheet1 = myWorkbook.sheet_by_index(0)  # 通过索引顺序获取。
# 方式三
# mySheet2 = myWorkbook.sheet_by_name('table')  # 通过名称获取。

# 获取行数和列数
nrows = mySheet.nrows
ncols = mySheet.ncols
print(nrows, ncols)

# 获取一行和一列
myRowValues = mySheet.row_values(0)  # i是行数，从0开始计数，返回list对象。

myColValues = mySheet.col_values(0)  # i是列数，从0开始计数，返回list对象。

print(myRowValues, myColValues)

# 读取单元格数据
# myCell = mySheet.cell(0, 0)  # 获取单元格，i是行数，j是列数，行数和列数都是从0开始计数。
# myCellValue = myCell.value  # 通过单元格获取单元格数据。
myCellValue = mySheet.cell_value(0, 0)  # 直接获取单元格数据，i是行数，j是列数，行数和列数都是从0开始计数。
print(myCellValue)

2. 写入

# 写入
import xlwt

# 创建Excel工作薄
myWorkbook = xlwt.Workbook()

# 添加Excel工作表
mySheet = myWorkbook.add_sheet('A Test Sheet')

# 写入数据
myStyle = xlwt.easyxf('font: name Times New Roman, color-index red, bold on', num_format_str='#,##0.00')   #数据格式
mySheet.write(1, 1, 1234.56, myStyle)
mySheet.write(2, 0, 1)                          #写入A3，数值等于1
mySheet.write(2, 1, 1)                          #写入B3，数值等于1
mySheet.write(2, 2, xlwt.Formula("A3+B3"))      #写入C3，数值等于2（A3+B3）

# 保存
myWorkbook.save('excelFile.xlsx')

xlutils结合xlrd可以达到修改excel文件目的

import xlrd
from xlutils.copy import copy

workbook = xlrd.open_workbook('excelFile.xlsx')
workbooknew = copy(workbook)
ws = workbooknew.get_sheet(0)
ws.write(3, 0, 'changed!')
workbooknew.save('excelFilecopy.xls')　

openpyxl可以对excel文件进行读写操作

from openpyxl import Workbook
from openpyxl import load_workbook
from openpyxl.writer.excel import ExcelWriter

workbook_ = load_workbook("data.xlsx")
sheetnames = workbook_.get_sheet_names()  # 获得表单名字
print(sheetnames)
sheet = workbook_.get_sheet_by_name(sheetnames[0])
print(sheet.cell(row=3, column=3).value)
sheet['A1'] = '47'
workbook_.save("data_new.xlsx")
wb = Workbook()
ws = wb.active
ws['A1'] = 4
wb.save("data_new2.xlsx")

xlsxwriter可以写excel文件并加上图表

import xlsxwriter

def get_chart(series):
    chart = workbook.add_chart({'type': 'line'})
    for ses in series:
        name = ses["name"]
        values = ses["values"]
        chart.add_series({
            'name': name,
            'categories': 'A2:A10',
            'values': values
        })
    chart.set_size({'width': 700, 'height': 350})
    return chart

if __name__ == '__main__':
    workbook = xlsxwriter.Workbook('H5应用中心关键数据及趋势.xlsx')
    worksheet = workbook.add_worksheet("每日PV,UV")
    headings = ['日期', '平均值']
    worksheet.write_row('A1', headings)
    index = 0
    for row in range(1, 10):
        for com in [0, 1]:
            worksheet.write(row, com, index)
            index += 1
    series = [{"name": "平均值", "values": "B2:B10"}]
    chart = get_chart(series)
    chart.set_title({'name': '每日页面分享数据'})
    worksheet.insert_chart('H7', chart)
    workbook.close()