readfile | 易学教程

微信小程序错误提示：readFile:fail parameter error: parameter.filePath should be String instead of Undefined;

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这个错误是在是由于之前写过类似的函数才检查出来的。遇到的错误是这样的重点是蓝色框中的元素类型错误，后来定位到该元素这里下面那个src请求的就是上面那个src，但是这应该定义成功一个全局变量，就不会报错了。在data数据里面定义一个src变量就可以了来源： https://www.cnblogs.com/wanys/p/11369961.html

skip some rows in read.csv in R

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I have a csv file which I read using the following function: csvData <- read.csv(file="pf.csv", colClasses=c(NA, NA,"NULL",NA,"NULL",NA,"NULL","NULL","NULL")) dimnames(csvData)[[2]]<- c("portfolio", "date", "ticker", "quantity") It reads all lines from that file. But i want to skip some rows from reading. The row should not read if the value of the ticker -column is: ABT or ADCT . Is it possible? sample of my csv file is as follows: RUS1000,01/29/1999,21st Centy Ins Group,TW.Z,90130N10,72096,1527.534,0.01,21.188 RUS1000,01/29/1999,3com Corp,COMS,88553510,358764,16861.908,0.16,47.000 RUS1000,01

Asynchronously reading and caching multiple files in nodejs

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问题 I have an array which keeps URL of several files. For example: var files = ['1.html', '2.html', '3.html']; I need to read them asynchronously and save them in an object named cache (cache = {}). To do this I used the code: for(var i = 0; i < files.length; i++){ require('fs').readFile(files[i], 'utf8', function (error,data) { cache[files[i]]=data; }); } In the end I have the result: cache = { undefined : 'File 3 content' } I do understand that the "readFile" acts after the loop is ended and it

How to read file with async/await properly?

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问题 I cannot figure out how async/await works. I slightly understands it but I can't make it work. function loadMonoCounter() { fs.readFileSync("monolitic.txt", "binary", async function(err, data) { return await new Buffer( data); }); } module.exports.read = function() { console.log(loadMonoCounter()); }; I know I could use readFileSync , but if I do, I know I'll never understand async/await and I'll just burry the issue. Goal: Call loadMonoCounter() and return the content of a file. That file is

PHP readfile vs. file_get_contents

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I have used following code to generate zip // push to download the zip header('Content-type: application/zip'); header('Content-Disposition: attachment; filename="'.$zip_name.'"'); readfile($zip_name); this code works fine but for unknown reasons was not working until I tried // push to download the zip header('Content-type: application/zip'); header('Content-Disposition: attachment; filename="'.$zip_name.'"'); echo file_get_contents($zip_name); I am curious about finding what is happening in both the cases Readfile will read the file directly into the output buffer, and file_get_contents will

Determining successful download using php readfile

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问题 I need to know if a user selected download then clicked the cancel button, which is not the same as readfile having an error. I have inspected the count returned by the readfile function, but it shows the bytes in the file even if the user canceled the download from the Save As dialog. The reason this is needed is because my site has a one-time download, where a member gives permission for another use to download their file one time, then the permission goes away. But if a member clicks the

How to get file read line by line

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问题 I have a file containing text in separate line. I want to display line first, and then if I press a button, the second line should be displayed in the TextView and the first line should disappear. Then, if I press it again, the third line should be displayed and so on. Should I have to use TextSwitcher or anything else? How can I do that? 回答1: You tagged it as "android-assets" so I'm going to assume your file is in the assets folder. Here: InputStream in; BufferedReader reader; String line;

string replace in a large file with php

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问题 I am trying to do a string replace for entire file in PHP. My file is over 100MB so I have to go line by line and can not use file_get_contents() . Is there a good solution to this? 回答1: If you aren't required to use PHP, I would highly recommend performing stuff like this from the command line. It's byfar the best tool for the job, and much easier to use. In any case, the sed (Stream Editor) command is what you are looking for: sed s/search/replace oldfilename > newfilename If you need case

Why does readfile() exhaust PHP memory?

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问题 I've seen many questions about how to efficiently use PHP to download files rather than allowing direct HTTP requests (to keep files secure, to track downloads, etc.). The answer is almost always PHP readfile(). Downloading large files reliably in PHP How to force download of big files without using too much memory? Best way to transparently log downloads? BUT, although it works great during testing with huge files, when it's on a live site with hundreds of users, downloads start to hang and

open read and close a file in 1 line of code

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Now I use: pageHeadSectionFile = open('pagehead.section.htm','r') output = pageHeadSectionFile.read() pageHeadSectionFile.close() But to make the code look better, I can do: output = open('pagehead.section.htm','r').read() When using the above syntax, how do I close the file to free up system resources? Tim Pietzcker You don't really have to close it - Python will do it automatically either during garbage collection or at program exit. But as @delnan noted, it's better practice to explicitly close it for various reasons. So, what you can do to keep it short, simple and explicit: with open(