seek

问题 I have a text file containing a number of records. Each record is stored on a single line that is 100 characters long. Let's say I want to directly access the nth record. I could do it using a for loop, reading in n lines until I get to the record. But how could I access it directly? 回答1: If the each line is exactly 100 characters long and the line ending is always \n (i.e. no \r\n stuff) and there's no blank lines and people won't use 1 tab for 8 spaces etc. you can use (with ifstream) fin

问题 I'm having difficulty writing VBA to accomplish a couple goals: 1. loop through address table ("SunstarAccountsInWebir_SarahTest") to separate out valid from invalid addresses. if invalid - export to different table. 2. If valid, match the address values to a 2nd table. If it matches, then insert the address values into the 2nd table. 3. If it doesn't match, then export to another different table The issue I'm getting is the exporting works, but I'm not seeing any action on condition 2 "valid

问题 Firstly, I want to insert characters into a text file. I want to print the characters (DAD1) into the middle of the text file ( HERE with DA D1) and the text file looks like this => @2100 AB CD EF 12 43 56 A3 B2 34 56 ..... ...............78 @ffb4 FF FF FF FF(***HERE***) @ffc0 FA 21 FA 21 .... I tried to use fprintf but it prints at the end of the file. Here is my coding part => fp = fopen("testing.txt", "r+"); if (fp) { while (c != EOF) { c = getc(fp); if (c == '@') { cout << c ; while (c !=

问题 Question again, guys. I use MediaExtractor and MediaCodec to play MP4 file on android device. Everything works fine until I try to add Extractor.seekto(). If I just play mp3 file with my player,seeking functions well. However, when I try it with MP4 file, the video is not updated. I tried to debug the code, finding out that the mPlayerExtractor.getSampleTrackIndex() always returns 1 (Refer to the audio track). But I do not know how to fix it. I cannot put all my code here. So please give me

问题 I am trying to write a program to do the following : specify a field from a record in a csv file called data. specify a field from a record in a csv file called log. compare the position of the two in the data and in the log. If they are on the same line proceed to write the record in the file called log in a new file called result. If the field does not match the record position in the log file proceed to move to the next record in the log file and compare it until a matching record is found

问题 I used this class to play my Wav file. Its very good but How to start my wav file on some position (KB or second)? auline.start(); int nBytesRead = 0; byte[] abData = new byte[EXTERNAL_BUFFER_SIZE]; try { while (nBytesRead != -1) { nBytesRead = audioInputStream.read(abData, 0, abData.length); System.out.println("s"); if (nBytesRead >= 0) auline.write(abData, 0, nBytesRead); } } catch (IOException e) { return; } finally { auline.drain(); auline.close(); } This is part of the code. 回答1: A Clip

问题 I have a file called fName.txt in a directory. Running the following python snippet (coming from a simulation) would add 6 numbers into 3 rows and 2 columns into the text file through executing the loop (containing the snippet) three times. However, I would like to empty the file completely before writing new data into it. (Otherwise running the script for many times would produce more than three rows needed for the simulation which would produce nonsense results; in other words the script

问题 I have a file with content: 0x11111111 0x22222222 0x33333333 0x44444444 And I'm reading it line by line using: f = open('test1', 'r') print "Register CIP_REGS_CONTROL value:" for i in range(4): content = f.read(11) f.seek(11, 1) print content Note that there're 11 bytes each line due to the '\n' char at the end. But the output is: 0x11111111 0x33333333 There's an empty line after the 1st and 3rd line, I don't know why it's like that. If I delete the '\n' in each line, and change the size of

问题 I have very large binary files with x number of int16 data points for y sensors, along with headers with some basic info. The binary file is written as y values for each sample time up to x samples, then another set of readings and so on. If I want all of the data, I am using numpy.fromfile() which works really nice and fast. However, if I only want a subset of sensor data or only specific sensors, I currently have a hideous double for loop, using file.seek() , file.read() , and struct.unpack

问题 My application uses lseek() to seek the desired position to write data. The file is successfully opened using open() and my application was able to use lseek() and write() lots of times. At a given time, for some users and not easily reproducable, lseek() returns -1 with an errno of 9. File is not closed before this and the filehandle (int) isn't reset. After this, another file is created; open() is okay again and lseek() and write() works again. To make it even worse, this user tried the