How to read a local text file?
You need to check for status 0 (as when loading files locally with XMLHttpRequest, you don’t get a status returned because it’s not from a Webserver) And specify file:// in your filename:
file-io
write() versus writelines() and concatenated strings
writelines expects an iterable of strings write expects a single string. line1 + “\n” + line2 merges those strings together into a single string before passing it to write. Note that if you have many lines, you may want to use “\n”.join(list_of_lines).
How to read a local text file?
You need to check for status 0 (as when loading files locally with XMLHttpRequest, you don’t get a status returned because it’s not from a Webserver) And specify file:// in your filename:
Writing a list to a file with Python
You can use a loop: In Python 2, you can also use If you’re keen on a single function call, at least remove the square brackets [], so that the strings to be printed get made one at a time (a genexp rather than a listcomp) — no reason to take up all the memory required … Read more
Read file line by line using ifstream in C++
First, make an ifstream: The two standard methods are: Assume that every line consists of two numbers and read token by token:int a, b; while (infile >> a >> b) { // process pair (a,b) } Line-based parsing, using string streams:#include <sstream> #include <string> std::string line; while (std::getline(infile, line)) { std::istringstream iss(line); int a, b; if … Read more
ValueError : I/O operation on closed file
Indent correctly; your for statement should be inside the with block: Outside the with block, the file is closed.
Read file line by line using ifstream in C++
First, make an ifstream: The two standard methods are: Assume that every line consists of two numbers and read token by token: int a, b; while (infile >> a >> b) { // process pair (a,b) } Line-based parsing, using string streams: #include <sstream> #include <string> std::string line; while (std::getline(infile, line)) { std::istringstream iss(line); int … Read more
Python open() gives FileNotFoundError/IOError: Errno 2 No such file or directory
Make sure the file exists: use os.listdir() to see the list of files in the current working directory Make sure you’re in the directory you think you’re in with os.getcwd() (if you launch your code from an IDE, you may well be in a different directory) You can then either: Call os.chdir(dir), dir being the … Read more
Print string to text file
It is strongly advised to use a context manager. As an advantage, it is made sure the file is always closed, no matter what: This is the explicit version (but always remember, the context manager version from above should be preferred): If you’re using Python2.6 or higher, it’s preferred to use str.format() For python2.7 and higher … Read more
How do I tell if a regular file does not exist in Bash?
The test command ([ here) has a “not” logical operator which is the exclamation point (similar to many other languages). Try this: