将数据框添加到Excel工作表

Question

I am trying to write a dataframe to excel using panda.ExcelWriter after reading it from a huge csv file.

This code updates the excel sheet but it doesn't appends the data to the excel which I want

import pandas as pd 

reader = pd.read_csv("H:/ram/temp/1.csv", delimiter = '\t' ,chunksize = 10000, names = ['neo_user_id', 
    'gender',
    'age_range',
    'main_geolocation', # (user identifier of the client)
    'interest_category_1',
    'interest_category_2',
    'interest_category_3',
    'first_day_identifier'
    ],  encoding="utf-8")

ew = pd.ExcelWriter('H:/ram/Formatted/SynthExport.xlsx', engine='xlsxwriter', options={'encoding':'utf-8'})
for chunks in reader:
    chunks.to_excel(ew, 'Sheet1' , encoding = 'utf-8')
    print len(chunks)
ew.save()

I also tried to use data.append() and data.to_excel doing this result is memory error. Since I am reading data in chunks is there any way to write the data to excel

I got it working by this code

import pandas as pd 
import xlsxwriter
reader = pd.read_csv("H:/ram/user_action_export.2014.01.csv", delimiter = '\t', chunksize = 1000, names = ['day_identifier', 
    'user_id',
    'site_id',
    'device', # (user identifier of the client)
    'geolocation',
    'referrer',
    'pageviews',
    ],  encoding="utf-8")

startrows = 0
ew = pd.ExcelWriter('H:/ram/Formatted/ActionExport.xlsx', engine='xlsxwriter', options={'encoding':'utf-8'})

for chunks in reader:
    chunks.to_excel(ew, 'Sheet1' , encoding = 'utf-8', startrow = startrows)
    startrows = startrows + len(chunks)
    print startrows 

ew.save()

But still take so much time

Answer 1

我不知道这是否是导致主要问题的原因，但是您不应该在块之间调用save() ，因为单次调用save()关闭xlsxwriter文件。