[英]How to open a huge excel file efficiently
我有一個150MB的單頁excel文件,使用以下內容在一台非常強大的機器上打開大約需要7分鍾:
# using python
import xlrd
wb = xlrd.open_workbook(file)
sh = wb.sheet_by_index(0)
有沒有辦法更快地打開excel文件? 我甚至對非常古怪的建議(例如hadoop,spark,c,java等)持開放態度。 理想情況下,我正在尋找一種在30秒內打開文件的方法,如果這不是夢想。 另外,上面的例子是使用python,但它不一定是python。
注意:這是來自客戶端的Excel文件。 在收到之前,它無法轉換為任何其他格式。 這不是我們的檔案
更新:回答一個代碼的工作示例將在30秒內打開以下200MB excel文件將獲得獎勵: https : //drive.google.com/file/d/0B_CXvCTOo7_2VW9id2VXRWZrbzQ/view? usp =sharing 。 該文件應該包含字符串(col 1),date(col 9)和number(col 11)。
大多數使用Office產品的編程語言都有一些中間層,這通常是瓶頸所在,一個很好的例子就是使用PIA的/ Interop或Open XML SDK。
將數據置於較低級別(繞過中間層)的一種方法是使用驅動程序。
150MB單頁excel文件,大約需要7分鍾。
我能做的最好的是135秒的130MB文件,大約快3倍:
Stopwatch sw = new Stopwatch();
sw.Start();
DataSet excelDataSet = new DataSet();
string filePath = @"c:\temp\BigBook.xlsx";
// For .XLSXs we use =Microsoft.ACE.OLEDB.12.0;, for .XLS we'd use Microsoft.Jet.OLEDB.4.0; with "';Extended Properties=\"Excel 8.0;HDR=YES;\"";
string connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source='" + filePath + "';Extended Properties=\"Excel 12.0;HDR=YES;\"";
using (OleDbConnection conn = new OleDbConnection(connectionString))
{
conn.Open();
OleDbDataAdapter objDA = new System.Data.OleDb.OleDbDataAdapter
("select * from [Sheet1$]", conn);
objDA.Fill(excelDataSet);
//dataGridView1.DataSource = excelDataSet.Tables[0];
}
sw.Stop();
Debug.Print("Load XLSX tool: " + sw.ElapsedMilliseconds + " millisecs. Records = " + excelDataSet.Tables[0].Rows.Count);
贏得7x64,Intel i5,2.3ghz,8GB內存,SSD250GB。
如果我也可以推薦硬件解決方案,如果您使用的是標准硬盤驅動器,請嘗試使用SSD解決它。
注意:我無法下載您的Excel電子表格示例,因為我在公司防火牆后面。
PS。 請參閱MSDN - 使用200 MB數據導入xlsx文件的最快方式, OleDB的共識是最快的。
PS 2.以下是使用python進行操作的方法: http : //code.activestate.com/recipes/440661-read-tabular-data-from-excel-spreadsheets-the-fast/
我設法使用.NET核心和Open XML SDK在大約30秒內讀取文件。
以下示例返回包含具有匹配類型的所有行和單元格的對象列表,它支持日期,數字和文本單元格。 該項目可在此處獲得: https : //github.com/xferaa/BigSpreadSheetExample/ (適用於Windows,Linux和Mac OS,不需要安裝Excel或任何Excel組件)。
public List<List<object>> ParseSpreadSheet()
{
List<List<object>> rows = new List<List<object>>();
using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(filePath, false))
{
WorkbookPart workbookPart = spreadsheetDocument.WorkbookPart;
WorksheetPart worksheetPart = workbookPart.WorksheetParts.First();
OpenXmlReader reader = OpenXmlReader.Create(worksheetPart);
Dictionary<int, string> sharedStringCache = new Dictionary<int, string>();
int i = 0;
foreach (var el in workbookPart.SharedStringTablePart.SharedStringTable.ChildElements)
{
sharedStringCache.Add(i++, el.InnerText);
}
while (reader.Read())
{
if(reader.ElementType == typeof(Row))
{
reader.ReadFirstChild();
List<object> cells = new List<object>();
do
{
if (reader.ElementType == typeof(Cell))
{
Cell c = (Cell)reader.LoadCurrentElement();
if (c == null || c.DataType == null || !c.DataType.HasValue)
continue;
object value;
switch(c.DataType.Value)
{
case CellValues.Boolean:
value = bool.Parse(c.CellValue.InnerText);
break;
case CellValues.Date:
value = DateTime.Parse(c.CellValue.InnerText);
break;
case CellValues.Number:
value = double.Parse(c.CellValue.InnerText);
break;
case CellValues.InlineString:
case CellValues.String:
value = c.CellValue.InnerText;
break;
case CellValues.SharedString:
value = sharedStringCache[int.Parse(c.CellValue.InnerText)];
break;
default:
continue;
}
if (value != null)
cells.Add(value);
}
} while (reader.ReadNextSibling());
if (cells.Any())
rows.Add(cells);
}
}
}
return rows;
}
我在一台三年前的筆記本電腦上運行該程序,該筆記本電腦配備SSD驅動器,8GB內存和Windows 10 64位上的Intel Core i7-4710 CPU @ 2.50GHz(兩個內核)。
請注意,雖然打開並將整個文件解析為字符串需要的時間少於30秒,但在我上次編輯的示例中使用對象時,使用我的筆記本電腦時,時間會增加到近50秒。 使用Linux,您的服務器可能會接近30秒。
訣竅是使用SAX方法,如下所述:
https://msdn.microsoft.com/en-us/library/office/gg575571.aspx
好吧,如果您的Excel將像您的示例( https://drive.google.com/file/d/0B_CXvCTOo7_2UVZxbnpRaEVnaFk/view?usp=sharing )一樣簡單,您可以嘗試將文件打開為一個zip文件並直接讀取每個xml:
Intel i5 4460,12 GB RAM,SSD Samsung EVO PRO。
如果你有很多內存ram:這段代碼需要很多內存,但需要20~25秒。 (你需要參數-Xmx7g)
package com.devsaki.opensimpleexcel;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.nio.charset.Charset;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.zip.ZipFile;
public class Multithread {
public static final char CHAR_END = (char) -1;
public static void main(String[] args) throws IOException, ExecutionException, InterruptedException {
String excelFile = "C:/Downloads/BigSpreadsheetAllTypes.xlsx";
ZipFile zipFile = new ZipFile(excelFile);
long init = System.currentTimeMillis();
ExecutorService executor = Executors.newFixedThreadPool(4);
char[] sheet1 = readEntry(zipFile, "xl/worksheets/sheet1.xml").toCharArray();
Future<Object[][]> futureSheet1 = executor.submit(() -> processSheet1(new CharReader(sheet1), executor));
char[] sharedString = readEntry(zipFile, "xl/sharedStrings.xml").toCharArray();
Future<String[]> futureWords = executor.submit(() -> processSharedStrings(new CharReader(sharedString)));
Object[][] sheet = futureSheet1.get();
String[] words = futureWords.get();
executor.shutdown();
long end = System.currentTimeMillis();
System.out.println("only read: " + (end - init) / 1000);
///Doing somethin with the file::Saving as csv
init = System.currentTimeMillis();
try (PrintWriter writer = new PrintWriter(excelFile + ".csv", "UTF-8");) {
for (Object[] rows : sheet) {
for (Object cell : rows) {
if (cell != null) {
if (cell instanceof Integer) {
writer.append(words[(Integer) cell]);
} else if (cell instanceof String) {
writer.append(toDate(Double.parseDouble(cell.toString())));
} else {
writer.append(cell.toString()); //Probably a number
}
}
writer.append(";");
}
writer.append("\n");
}
}
end = System.currentTimeMillis();
System.out.println("Main saving to csv: " + (end - init) / 1000);
}
private static final DateTimeFormatter formatter = DateTimeFormatter.ISO_DATE_TIME;
private static final LocalDateTime INIT_DATE = LocalDateTime.parse("1900-01-01T00:00:00+00:00", formatter).plusDays(-2);
//The number in excel is from 1900-jan-1, so every number time that you get, you have to sum to that date
public static String toDate(double s) {
return formatter.format(INIT_DATE.plusSeconds((long) ((s*24*3600))));
}
public static String readEntry(ZipFile zipFile, String entry) throws IOException {
System.out.println("Initialing readEntry " + entry);
long init = System.currentTimeMillis();
String result = null;
try (BufferedReader br = new BufferedReader(new InputStreamReader(zipFile.getInputStream(zipFile.getEntry(entry)), Charset.forName("UTF-8")))) {
br.readLine();
result = br.readLine();
}
long end = System.currentTimeMillis();
System.out.println("readEntry '" + entry + "': " + (end - init) / 1000);
return result;
}
public static String[] processSharedStrings(CharReader br) throws IOException {
System.out.println("Initialing processSharedStrings");
long init = System.currentTimeMillis();
String[] words = null;
char[] wordCount = "Count=\"".toCharArray();
char[] token = "<t>".toCharArray();
String uniqueCount = extractNextValue(br, wordCount, '"');
words = new String[Integer.parseInt(uniqueCount)];
String nextWord;
int currentIndex = 0;
while ((nextWord = extractNextValue(br, token, '<')) != null) {
words[currentIndex++] = nextWord;
br.skip(11); //you can skip at least 11 chars "/t></si><si>"
}
long end = System.currentTimeMillis();
System.out.println("SharedStrings: " + (end - init) / 1000);
return words;
}
public static Object[][] processSheet1(CharReader br, ExecutorService executorService) throws IOException, ExecutionException, InterruptedException {
System.out.println("Initialing processSheet1");
long init = System.currentTimeMillis();
char[] dimensionToken = "dimension ref=\"".toCharArray();
String dimension = extractNextValue(br, dimensionToken, '"');
int[] sizes = extractSizeFromDimention(dimension.split(":")[1]);
br.skip(30); //Between dimension and next tag c exists more or less 30 chars
Object[][] result = new Object[sizes[0]][sizes[1]];
int parallelProcess = 8;
int currentIndex = br.currentIndex;
CharReader[] charReaders = new CharReader[parallelProcess];
int totalChars = Math.round(br.chars.length / parallelProcess);
for (int i = 0; i < parallelProcess; i++) {
int endIndex = currentIndex + totalChars;
charReaders[i] = new CharReader(br.chars, currentIndex, endIndex, i);
currentIndex = endIndex;
}
Future[] futures = new Future[parallelProcess];
for (int i = charReaders.length - 1; i >= 0; i--) {
final int j = i;
futures[i] = executorService.submit(() -> inParallelProcess(charReaders[j], j == 0 ? null : charReaders[j - 1], result));
}
for (Future future : futures) {
future.get();
}
long end = System.currentTimeMillis();
System.out.println("Sheet1: " + (end - init) / 1000);
return result;
}
public static void inParallelProcess(CharReader br, CharReader back, Object[][] result) {
System.out.println("Initialing inParallelProcess : " + br.identifier);
char[] tokenOpenC = "<c r=\"".toCharArray();
char[] tokenOpenV = "<v>".toCharArray();
char[] tokenAttributS = " s=\"".toCharArray();
char[] tokenAttributT = " t=\"".toCharArray();
String v;
int firstCurrentIndex = br.currentIndex;
boolean first = true;
while ((v = extractNextValue(br, tokenOpenC, '"')) != null) {
if (first && back != null) {
int sum = br.currentIndex - firstCurrentIndex - tokenOpenC.length - v.length() - 1;
first = false;
System.out.println("Adding to : " + back.identifier + " From : " + br.identifier);
back.plusLength(sum);
}
int[] indexes = extractSizeFromDimention(v);
int s = foundNextTokens(br, '>', tokenAttributS, tokenAttributT);
char type = 's'; //3 types: number (n), string (s) and date (d)
if (s == 0) { // Token S = number or date
char read = br.read();
if (read == '1') {
type = 'n';
} else {
type = 'd';
}
} else if (s == -1) {
type = 'n';
}
String c = extractNextValue(br, tokenOpenV, '<');
Object value = null;
switch (type) {
case 'n':
value = Double.parseDouble(c);
break;
case 's':
try {
value = Integer.parseInt(c);
} catch (Exception ex) {
System.out.println("Identifier Error : " + br.identifier);
}
break;
case 'd':
value = c.toString();
break;
}
result[indexes[0] - 1][indexes[1] - 1] = value;
br.skip(7); ///v></c>
}
}
static class CharReader {
char[] chars;
int currentIndex;
int length;
int identifier;
public CharReader(char[] chars) {
this.chars = chars;
this.length = chars.length;
}
public CharReader(char[] chars, int currentIndex, int length, int identifier) {
this.chars = chars;
this.currentIndex = currentIndex;
if (length > chars.length) {
this.length = chars.length;
} else {
this.length = length;
}
this.identifier = identifier;
}
public void plusLength(int n) {
if (this.length + n <= chars.length) {
this.length += n;
}
}
public char read() {
if (currentIndex >= length) {
return CHAR_END;
}
return chars[currentIndex++];
}
public void skip(int n) {
currentIndex += n;
}
}
public static int[] extractSizeFromDimention(String dimention) {
StringBuilder sb = new StringBuilder();
int columns = 0;
int rows = 0;
for (char c : dimention.toCharArray()) {
if (columns == 0) {
if (Character.isDigit(c)) {
columns = convertExcelIndex(sb.toString());
sb = new StringBuilder();
}
}
sb.append(c);
}
rows = Integer.parseInt(sb.toString());
return new int[]{rows, columns};
}
public static int foundNextTokens(CharReader br, char until, char[]... tokens) {
char character;
int[] indexes = new int[tokens.length];
while ((character = br.read()) != CHAR_END) {
if (character == until) {
break;
}
for (int i = 0; i < indexes.length; i++) {
if (tokens[i][indexes[i]] == character) {
indexes[i]++;
if (indexes[i] == tokens[i].length) {
return i;
}
} else {
indexes[i] = 0;
}
}
}
return -1;
}
public static String extractNextValue(CharReader br, char[] token, char until) {
char character;
StringBuilder sb = new StringBuilder();
int index = 0;
while ((character = br.read()) != CHAR_END) {
if (index == token.length) {
if (character == until) {
return sb.toString();
} else {
sb.append(character);
}
} else {
if (token[index] == character) {
index++;
} else {
index = 0;
}
}
}
return null;
}
public static int convertExcelIndex(String index) {
int result = 0;
for (char c : index.toCharArray()) {
result = result * 26 + ((int) c - (int) 'A' + 1);
}
return result;
}
}
舊答案(不需要參數Xms7g,因此占用更少內存):使用HDD打開和讀取示例文件約35秒(200MB),SDD需要少一點(30秒)。
這里的代碼是: https : //github.com/csaki/OpenSimpleExcelFast.git
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.nio.charset.Charset;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.zip.ZipFile;
public class Launcher {
public static final char CHAR_END = (char) -1;
public static void main(String[] args) throws IOException, ExecutionException, InterruptedException {
long init = System.currentTimeMillis();
String excelFile = "D:/Downloads/BigSpreadsheet.xlsx";
ZipFile zipFile = new ZipFile(excelFile);
ExecutorService executor = Executors.newFixedThreadPool(4);
Future<String[]> futureWords = executor.submit(() -> processSharedStrings(zipFile));
Future<Object[][]> futureSheet1 = executor.submit(() -> processSheet1(zipFile));
String[] words = futureWords.get();
Object[][] sheet1 = futureSheet1.get();
executor.shutdown();
long end = System.currentTimeMillis();
System.out.println("Main only open and read: " + (end - init) / 1000);
///Doing somethin with the file::Saving as csv
init = System.currentTimeMillis();
try (PrintWriter writer = new PrintWriter(excelFile + ".csv", "UTF-8");) {
for (Object[] rows : sheet1) {
for (Object cell : rows) {
if (cell != null) {
if (cell instanceof Integer) {
writer.append(words[(Integer) cell]);
} else if (cell instanceof String) {
writer.append(toDate(Double.parseDouble(cell.toString())));
} else {
writer.append(cell.toString()); //Probably a number
}
}
writer.append(";");
}
writer.append("\n");
}
}
end = System.currentTimeMillis();
System.out.println("Main saving to csv: " + (end - init) / 1000);
}
private static final DateTimeFormatter formatter = DateTimeFormatter.ISO_DATE_TIME;
private static final LocalDateTime INIT_DATE = LocalDateTime.parse("1900-01-01T00:00:00+00:00", formatter).plusDays(-2);
//The number in excel is from 1900-jan-1, so every number time that you get, you have to sum to that date
public static String toDate(double s) {
return formatter.format(INIT_DATE.plusSeconds((long) ((s*24*3600))));
}
public static Object[][] processSheet1(ZipFile zipFile) throws IOException {
String entry = "xl/worksheets/sheet1.xml";
Object[][] result = null;
char[] dimensionToken = "dimension ref=\"".toCharArray();
char[] tokenOpenC = "<c r=\"".toCharArray();
char[] tokenOpenV = "<v>".toCharArray();
char[] tokenAttributS = " s=\"".toCharArray();
char[] tokenAttributT = " t=\"".toCharArray();
try (BufferedReader br = new BufferedReader(new InputStreamReader(zipFile.getInputStream(zipFile.getEntry(entry)), Charset.forName("UTF-8")))) {
String dimension = extractNextValue(br, dimensionToken, '"');
int[] sizes = extractSizeFromDimention(dimension.split(":")[1]);
br.skip(30); //Between dimension and next tag c exists more or less 30 chars
result = new Object[sizes[0]][sizes[1]];
String v;
while ((v = extractNextValue(br, tokenOpenC, '"')) != null) {
int[] indexes = extractSizeFromDimention(v);
int s = foundNextTokens(br, '>', tokenAttributS, tokenAttributT);
char type = 's'; //3 types: number (n), string (s) and date (d)
if (s == 0) { // Token S = number or date
char read = (char) br.read();
if (read == '1') {
type = 'n';
} else {
type = 'd';
}
} else if (s == -1) {
type = 'n';
}
String c = extractNextValue(br, tokenOpenV, '<');
Object value = null;
switch (type) {
case 'n':
value = Double.parseDouble(c);
break;
case 's':
value = Integer.parseInt(c);
break;
case 'd':
value = c.toString();
break;
}
result[indexes[0] - 1][indexes[1] - 1] = value;
br.skip(7); ///v></c>
}
}
return result;
}
public static int[] extractSizeFromDimention(String dimention) {
StringBuilder sb = new StringBuilder();
int columns = 0;
int rows = 0;
for (char c : dimention.toCharArray()) {
if (columns == 0) {
if (Character.isDigit(c)) {
columns = convertExcelIndex(sb.toString());
sb = new StringBuilder();
}
}
sb.append(c);
}
rows = Integer.parseInt(sb.toString());
return new int[]{rows, columns};
}
public static String[] processSharedStrings(ZipFile zipFile) throws IOException {
String entry = "xl/sharedStrings.xml";
String[] words = null;
char[] wordCount = "Count=\"".toCharArray();
char[] token = "<t>".toCharArray();
try (BufferedReader br = new BufferedReader(new InputStreamReader(zipFile.getInputStream(zipFile.getEntry(entry)), Charset.forName("UTF-8")))) {
String uniqueCount = extractNextValue(br, wordCount, '"');
words = new String[Integer.parseInt(uniqueCount)];
String nextWord;
int currentIndex = 0;
while ((nextWord = extractNextValue(br, token, '<')) != null) {
words[currentIndex++] = nextWord;
br.skip(11); //you can skip at least 11 chars "/t></si><si>"
}
}
return words;
}
public static int foundNextTokens(BufferedReader br, char until, char[]... tokens) throws IOException {
char character;
int[] indexes = new int[tokens.length];
while ((character = (char) br.read()) != CHAR_END) {
if (character == until) {
break;
}
for (int i = 0; i < indexes.length; i++) {
if (tokens[i][indexes[i]] == character) {
indexes[i]++;
if (indexes[i] == tokens[i].length) {
return i;
}
} else {
indexes[i] = 0;
}
}
}
return -1;
}
public static String extractNextValue(BufferedReader br, char[] token, char until) throws IOException {
char character;
StringBuilder sb = new StringBuilder();
int index = 0;
while ((character = (char) br.read()) != CHAR_END) {
if (index == token.length) {
if (character == until) {
return sb.toString();
} else {
sb.append(character);
}
} else {
if (token[index] == character) {
index++;
} else {
index = 0;
}
}
}
return null;
}
public static int convertExcelIndex(String index) {
int result = 0;
for (char c : index.toCharArray()) {
result = result * 26 + ((int) c - (int) 'A' + 1);
}
return result;
}
}
Python的Pandas庫可用於保存和處理您的數據,但使用它來直接加載.xlsx
文件將非常慢,例如使用read_excel()
。
一種方法是使用Python自動使用Excel本身將文件轉換為CSV,然后使用Pandas使用read_csv()
加載生成的CSV文件。 這將為您提供良好的加速,但不會低於30秒:
import win32com.client as win32
import pandas as pd
from datetime import datetime
print ("Starting")
start = datetime.now()
# Use Excel to load the xlsx file and save it in csv format
excel = win32.gencache.EnsureDispatch('Excel.Application')
wb = excel.Workbooks.Open(r'c:\full path\BigSpreadsheet.xlsx')
excel.DisplayAlerts = False
wb.DoNotPromptForConvert = True
wb.CheckCompatibility = False
print('Saving')
wb.SaveAs(r'c:\full path\temp.csv', FileFormat=6, ConflictResolution=2)
excel.Application.Quit()
# Use Pandas to load the resulting CSV file
print('Loading CSV')
df = pd.read_csv(r'c:\full path\temp.csv', dtype=str)
print(df.shape)
print("Done", datetime.now() - start)
列類型
該類型的列可以通過傳遞指定dtype
和converters
和parse_dates
:
df = pd.read_csv(r'c:\full path\temp.csv', dtype=str, converters={10:int}, parse_dates=[8], infer_datetime_format=True)
您還應該指定infer_datetime_format=True
,因為這將大大加快日期轉換速度。
nfer_datetime_format
:boolean,默認為False如果啟用了True和parse_dates,pandas將嘗試推斷列中日期時間字符串的格式,如果可以推斷,請切換到更快的解析方法。 在某些情況下,這可以將解析速度提高5-10倍。
如果日期的格式為DD/MM/YYYY
添加dayfirst=True
。
選擇性的列
如果您實際上只需要處理第1 9 11
列,那么您可以通過指定usecols=[0, 8, 10]
來進一步減少資源,如下所示:
df = pd.read_csv(r'c:\full path\temp.csv', dtype=str, converters={10:int}, parse_dates=[1], dayfirst=True, infer_datetime_format=True, usecols=[0, 8, 10])
結果數據幀將只包含這3列數據。
RAM驅動器
使用RAM驅動器存儲臨時CSV文件可以進一步加快加載時間。
注意:這假設您使用的是帶有Excel的Windows PC。
我正在使用Dell Precision T1700工作站並使用c#我能夠在大約24秒內打開文件並閱讀它的內容,只需使用標准代碼即可使用互操作服務打開工作簿。 這里使用對Microsoft Excel 15.0對象庫的引用是我的代碼。
我的使用陳述:
using System.Runtime.InteropServices;
using Excel = Microsoft.Office.Interop.Excel;
用於打開和閱讀工作簿的代碼:
public partial class MainWindow : Window {
public MainWindow() {
InitializeComponent();
Excel.Application xlApp;
Excel.Workbook wb;
Excel.Worksheet ws;
xlApp = new Excel.Application();
xlApp.Visible = false;
xlApp.ScreenUpdating = false;
wb = xlApp.Workbooks.Open(@"Desired Path of workbook\Copy of BigSpreadsheet.xlsx");
ws = wb.Sheets["Sheet1"];
//string rng = ws.get_Range("A1").Value;
MessageBox.Show(ws.get_Range("A1").Value);
Marshal.FinalReleaseComObject(ws);
wb.Close();
Marshal.FinalReleaseComObject(wb);
xlApp.Quit();
Marshal.FinalReleaseComObject(xlApp);
GC.Collect();
GC.WaitForPendingFinalizers();
}
}
我已經創建了一個示例Java程序,它可以在我的筆記本電腦(Intel i7 4核,16 GB RAM)中加載文件~40秒。
https://github.com/skadyan/largefile
該程序使用Apache POI庫使用XSSF SAX API加載.xlsx文件。
回調接口com.stackoverlfow.largefile.RecordHandler
實現可用於處理從excel加載的數據。 此接口僅定義一個采用三個參數的方法
data map
:映射:excel單元格引用和excel格式化單元格值 com.stackoverlfow.largefile.Main
類演示了此接口的一個基本實現,它只是在控制台上打印行號。
更新
woodstox解析器似乎比標准SAXReader
具有更好的性能。 (代碼在repo中更新)。
另外,為了滿足所需的性能要求,您可以考慮重新實現org.apache.poi...XSSFSheetXMLHandler
。 在實現中,可以實現更優化的字符串/文本值處理,並且可以跳過不必要的文本格式化操作。
看起來在Python中幾乎無法實現。 如果我們解壓縮工作表數據文件,那么通過基於C的迭代SAX解析器(使用lxml
,一個非常快速的libxml2
包裝器)將需要30秒才能通過它:
from __future__ import print_function
from lxml import etree
import time
start_ts = time.time()
for data in etree.iterparse(open('xl/worksheets/sheet1.xml'), events=('start',),
collect_ids=False, resolve_entities=False,
huge_tree=True):
pass
print(time.time() - start_ts)
樣本輸出:27.2134890556
順便說一句,Excel本身需要大約40秒來加載工作簿。
c#和ole解決方案仍有一些瓶頸。所以我用c ++和ado測試它。
_bstr_t connStr(makeConnStr(excelFile, header).c_str());
TESTHR(pRec.CreateInstance(__uuidof(Recordset)));
TESTHR(pRec->Open(sqlSelectSheet(connStr, sheetIndex).c_str(), connStr, adOpenStatic, adLockOptimistic, adCmdText));
while(!pRec->adoEOF)
{
for(long i = 0; i < pRec->Fields->GetCount(); ++i)
{
_variant_t v = pRec->Fields->GetItem(i)->Value;
if(v.vt == VT_R8)
num[i] = v.dblVal;
if(v.vt == VT_BSTR)
str[i] = v.bstrVal;
++cellCount;
}
pRec->MoveNext();
}
在i5-4460和HDD機器中,我發現xls中的500萬個單元將需要1.5s。但是xlsx中的相同數據將需要2.829。因此可以在30秒內操作您的數據。
如果您確實需要30秒以下,請使用RAM驅動器來減少文件IO。它將顯着改善您的過程。 我無法下載您的數據進行測試,所以請告訴我結果。
另一種應該在很大程度上改善負載/運行時間的方法是RAMDrive
為您的文件創建一個有足夠空間的RAMDrive,以及10%...... 20%的額外空間......
復制RAMDrive的文件...
從那里加載文件...根據您的驅動器和文件系統,速度的提升應該是巨大的......
我最喜歡的是IMDisk工具包
( https://sourceforge.net/projects/imdisk-toolkit/ )這里有一個強大的命令行來編寫腳本...
我還推薦SoftPerfect ramdisk
( http://www.majorgeeks.com/files/details/softperfect_ram_disk.html )
但這也取決於你的操作系統......
我想了解有關您打開文件的系統的更多信息...無論如何:
在系統中查找名為的Windows更新
“辦公室文件驗證加載項...”
如果你有它...卸載它...
該文件應該加載更快
特別是如果是分享的話
您是否嘗試過按需加載工作表 ,從xlrd版本0.7.1開始可用?
為此,您需要將on_demand=True
傳遞給open_workbook()
。
xlrd.open_workbook(filename = None,logfile = <_ io.TextIOWrapper name =''mode ='w'coding ='UTF-8'>,verbosity = 0,use_mmap = 1,file_contents = None,encoding_override = None,formatting_info = False,on_demand = False,ragged_rows = False)
我發現用於讀取xlsx文件的其他潛在python解決方案:
嘗試使用openpyxl庫的只讀模式 ,該模式聲稱對大文件的內存使用情況也進行了優化。
from openpyxl import load_workbook wb = load_workbook(filename='large_file.xlsx', read_only=True) ws = wb['big_data'] for row in ws.rows: for cell in row: print(cell.value)
如果您在Windows上運行,可以使用PyWin32和'Excel.Application'
import time import win32com.client as win32 def excel(): xl = win32.gencache.EnsureDispatch('Excel.Application') ss = xl.Workbooks.Add() ...
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