File Operation
File operations such as reading and writing are commonly used in day-to-day development, especially when we want to dump some data from the program to a text file.
Parameters
The opening modes in Python are the same as C fopen()
std library function.
The BSD fopen
manpage defines them as follows:
The argument mode points to a string beginning with one of the following
sequences (Additional characters may follow these sequences.):
- “r” Open text file for reading. The stream is positioned at the
beginning of the file. - “r+” Open for reading and writing. The stream is positioned at the
beginning of the file. - “w” Truncate file to zero length or create text file for writing.
The stream is positioned at the beginning of the file. - “w+” Open for reading and writing. The file is created if it does not
exist.Otherwise it is truncated. The stream is positioned at
the beginning of the file. - “a” Open for writing. The file is created if it does not exist. The
stream is positioned at the end of the file. Subsequent writes
to the file will always end up at the then current end offile ,
irrespective of any interveningfseek (3) or similar. - “a+” Open for reading and writing. The file is created if it does not
exist. The stream is positioned at the end of the file. Subsequent writes to the file will always end up at the then current
end offile , irrespective of any interveningfseek (3) or simil
C Write File Example
#include <stdio.h>
#include <stdlib.h>
int main() {
FILE *fp;
// Open file
fp=fopen("test.txt", "a");
if(fp == NULL) exit(-1);
for(int i = 0; i < 100; i++){
fprintf(fp, "%d \n", i);
}
// Close file
fclose(fp);
}