file-read | 易学教程

How do I read and append to a text file in one pass?

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问题 I want to check if a string is inside a text file and then append that string if it's not there. I know I can probably do that by creating two separate with methods, one for reading and another for appending, but is it possible to read and append inside the same with method? The closest I came up with is this: with open("file.txt","r+") as file: content=file.read() print("aaa" in content) file.seek(len(content)) file.write("\nccccc") My file.txt: aaaaa bbbbb When I run the code for the first

Can you read line by line in javascript?

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问题 Is there any way to read a file line by line in javascript, specifically this file which is a dictionary. I was trying to build a replica of a java anagram solver I made a few months ago, but hit this problem of not being able to read a file line by line. I could download the file and store it locally if that would make any difference to being able to read it. 回答1: Use YQL: http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20html%20where%20url%3D%22http%3A%2F%2Fdocs.oracle.com

Clearest way to read and print .txt file lines in C

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问题 There are a bunch of ways describing how to use various methods to print out lines of a text file on this site: Posix-style, reading IP addresses, Fixed line length. They all seem to be tailored to a specific example. It would be great to have the Clearest and Most Concise and Easiest way to simply: print each line of any text file to the screen. Preferably with detailed explanations of what each line does. Points for brevity and clarity. 回答1: #include <stdio.h> static void cat(FILE *fp) {

Which function should I use to read unstructured text file into R? [closed]

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问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 6 years ago . This is my first ever question here and I'm new to R, trying to figure out my first step in how to do data processing, please keep it easy : ) I'm wondering what would be the best function and a useful data structure in R to load unstructured text data for further processing. For

Multiline file read in Python

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问题 I am looking for a method in Python which can read multiple lines from a file(10 lines at a time). I have already looked into readlines(sizehint) , I tried to pass value 10 but doesn't read only 10 lines. It actually reads till end of the file(I have tried on the small file). Each line is 11 bytes long and each read should fetch me 10 lines each time. If less than 10 lines are found then return only those lines. My actual file contains more than 150K lines. Any idea how I can achieve this?

Read file and get key=value without using java.util.Properties

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问题 I'm building a RMI game and the client would load a file that has some keys and values which are going to be used on several different objects. It is a save game file but I can't use java.util.Properties for this (it is under the specification). I have to read the entire file and ignore commented lines and the keys that are not relevant in some classes. These properties are unique but they may be sorted in any order. My file current file looks like this: # Bio playerOrigin=Newlands

Fastest file reading in a multi-threaded application

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问题 I have to read a 8192x8192 matrix into memory. I want to do it as fast as possible. Right now I have this structure: char inputFile[8192][8192*4]; // I know the numbers are at max 3 digits int8_t matrix[8192][8192]; // Matrix to be populated // Read entire file line by line using fgets while (fgets (inputFile[lineNum++], MAXCOLS, fp)); //Populate the matrix in parallel, for (t = 0; t < NUM_THREADS; t++){ pthread_create(&threads[t], NULL, ParallelRead, (void *)t); } In the function

Efficient way to read file multiple line one time?

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I am now trying to handle a large file (several GB), so I am thinking to use multi-thread. The file is multiple lines of data like: data1 attr1.1 attr1.2 attr1.3 data2 attr2.1 attr2.2 attr2.3 data3 attr3.1 attr3.2 attr3.3 I am thinking to use one thread read multiple lines first to a buffer1, and then one other thread to handle the data in buffer1 line by line, while the reading thread start to read file to buffer2. Then the handling thread continues when buffer2 is ready, and the reading thread read to buffer1 again. Now I finished the handler part by using freads for small file (several KB),

Read file and get key=value without using java.util.Properties

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I'm building a RMI game and the client would load a file that has some keys and values which are going to be used on several different objects. It is a save game file but I can't use java.util.Properties for this (it is under the specification). I have to read the entire file and ignore commented lines and the keys that are not relevant in some classes. These properties are unique but they may be sorted in any order. My file current file looks like this: # Bio playerOrigin=Newlands playerClass=Warlock # Armor playerHelmet=empty playerUpperArmor=armor900 playerBottomArmor=armor457 playerBoots

Fastest file reading in a multi-threaded application

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I have to read a 8192x8192 matrix into memory. I want to do it as fast as possible. Right now I have this structure: char inputFile[8192][8192*4]; // I know the numbers are at max 3 digits int8_t matrix[8192][8192]; // Matrix to be populated // Read entire file line by line using fgets while (fgets (inputFile[lineNum++], MAXCOLS, fp)); //Populate the matrix in parallel, for (t = 0; t < NUM_THREADS; t++){ pthread_create(&threads[t], NULL, ParallelRead, (void *)t); } In the function ParallelRead , I parse each line, do atoi and populate the matrix. The parallelism is line-wise like thread t