filereader | 易学教程

What do I have to add at the beginning of this loop?

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问题 how I can read the following files using the for loop: (can the loop ignore the characters in filenames?) abc-1.TXT cde-2.TXT ser-3.TXT wsz-4.TXT aqz-5.TXT iop-6.TXT What do I have to add at the beginning of this loop ?? for i = 1:1:6 nom_fichier = strcat(['MyFile\.......' num2str(i) '.TXT']); 回答1: You can avoid constructing the filenames by using the DIR command. For instance: myfiles = dir('*.txt'); for i = 1:length(myfiles) nom_fichier = myfiles(i).name; ...do processing here... end 回答2:

Javascript, spliced FileReader for large files with Promises, how?

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问题 I'm trying to use FileReader to read several files sequentially using promises for that. The problem is that I need to divide the reading operations in several chunks to make them doable. By doing so, I lose the Promise chain. This is what happen in the following code, where I get the console log here , then catched (meaning I've lost the chain), then inside and then finished . Somehow the Promise in upload is not respected. Here it is the code (please go to the last EDIT, I keep the original

How to load large local files using JavaScript?

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问题 Is there a way to handle very large files(like 2GB and over) locally in JavaScript without crashing the browser? *I am aware of the input tag and the FileReader API, but it seems there is nothing like Node.js streams. 回答1: FileReader enables you to read contents of files asynchronously. With respect to large file (2GB in your case), you can use function/method FileReader.readAsArrayBuffer() to read a certain chunk size of a file in the memory hence this won't crash your browser, this blog is

FileReader.result

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FileReader.result 该属性返回文件的内容。此属性仅在读取操作完成后才有效，并且数据的格式取决于用于启动读取操作的方法。 FileReader ] **result** 句法 var file = instanceOfFileReader .result 值适当的字符串或 ArrayBuffer ]基于哪种读取方法来启动读取操作。该值是 null 读数是否尚未完成或未成功。结果类型如下所述。方法描述 readAsArrayBuffer() 的 result 是JavaScript ArrayBuffer 包含的二进制数据。 readAsBinaryString() 该 result 包含在一个字符串的文件的原始的二进制数据。 readAsDataURL() 该 result 是一个字符串 data: 表示文件的传输数据的URL。 readAsText() 该 result 是一个字符串文本。例此示例展示了一个函数， read() 该函数从file input读取文件。它的工作方式是创建一个 FileReader 对象并为加载事件创建一个侦听器，以便在读取文件时 result 获取并将其传递给提供给的回调函数 read() 。内容作为原始文本数据处理。 var fileInput = document.querySelector('input[type=

How to capture FileReader base64 as variable?

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This prints base64 out to console: function getBase64(file) { var reader = new FileReader(); reader.readAsDataURL(file); reader.onload = function() { console.log(reader.result); }; reader.onerror = function(error) { console.log('Error: ', error); }; } var file = document.querySelector('#files > input[type="file"]').files[0]; getBase64(file); // prints the base64 string Source: https://stackoverflow.com/a/36281449/1063287 jsFiddle: jsFiddle demo of the above working code I want to be able to assign the base64 to a variable, so I tried the following, based on this answer : function getBase64

Java FileReader not finding files

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问题 I decided to start a new question so it can strictly focus on the FileReader errors. This is a method that takes in a file name, and a desired output name for a new file. Say the inputted filename is "hello.txt"... the method makes it something like "/home/User/hello.txt", which goes into the FileReader as a parameter. The problem is that I get this as output "/home/User/hello.txt (No such file or directory)", even though the file does exist and the directory structure and permissions are

How to read file on Windows and Linux from Java

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问题 I have a xml file located in D:\XML\RequestXML and I am reading xml file in this folder from a FileReader . In my program I hard coded the file path /XML/RequestXML/ . This works fine with the windows environment. In windows JBoss is in D:\jbossdistrib\jboss . I created the folder structure in linux /usr/XML/RequestXML/ . And add the xml in to RequestXML folder. JBoss is in /usr/jbossdistrib/jboss/ path. But my application can not find the file specified in /XML/RequestXML/ in linux

How to implement Progress Bar and Callbacks with async nature of the FileReader

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I have the FileReader API called within a for loop to iterate through multiple file objects. I'm using FileReader to essentially display preview of images. function() { for (var i in Files) { var fileReader = new FileReader(); fileReader.readAsBinaryString(Files[i]); fileReader.onload = function() { // do something on FileReader onload } fileReader.onprogress = function(data) { if (data.lengthComputable) { var progress = parseInt( ((data.loaded / data.total) * 100), 10 ); console.log(progress); } } } // do something on completion of FileReader process // actions here run before completion of

how to read json object in python [duplicate]

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This question already has an answer here: can't read json file with python. getting type error: json object is 'TextIOWrapper' 3 answers i have json file named "panamaleaks50k.json" . I want to get ['text'] field from json file but it shows me following error the JSON object must be str, bytes or bytearray, not 'TextIOWrapper' this is my code with open('C:/Users/bilal butt/Desktop/PanamalEakJson.json','r') as lst: b = json.loads(lst) print(b['text']) my json file look [ { "fullname": "Mohammad Fayyaz", "id": "885800668862263296", "likes": "0", "replies": "0", "retweets": "0", "text": "Love of

The FileReader cannot find my text file

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I have a simple text file and for some reason, it cannot be found. I don't see anything wrong with the code because I got it from a site, and I am starting to think that I didn't place the text file in the right place. Any suggestion please? Code: import java.io.BufferedReader; import java.io.File; import java.io.FileReader; import java.io.IOException; import java.util.ArrayList; import java.nio.file.Path; import java.nio.file.Paths; public class MainFavorites { public static void main(String[] args) throws IOException { /** * finds pathway to the file */ // File file = new File(