In this example, we are simply performing the looping on the test. The goal of the program is to print the file contents, here contents are of multiple lines. In the below example we have taken two lines, We can explain the below example in the following steps.
This is a guide to Ruby Read File. Here we also discuss the Introduction and how to read file in ruby using various methods along with examples and its code implementation. You may also have a look at the following articles to learn more —. Submit Next Question. By signing up, you agree to our Terms of Use and Privacy Policy. Forgot Password? Using Ada. Directories to first ask for the file size and then Ada. On Linux you can use the command " limit stacksize M " to increase the available stack for your processes to 1Gb, which gives your program more freedom to use the stack for allocating objects.
Mapping the whole file into the address space of your process and then overlaying the file with a String object. Character encodings and their handling are not really specified in Ada. What Ada does specify is three different character types and corresponding string types :.
The book can contain new page s and new line s, are not of any particular character set, hence are system independent. The character set is set by a call to make conv , eg make conv tape, ebcdic conv ; - c. Once a "book" has been read into a book array it can still be associated with a virtual file and again be accessed with standard file routines such as readf , printf , putf , getf , new line etc. This means data can be directly manipulated from a array cached in "core" using transput stdio routines.
Hopper only stores 1 BM of characters for each string variable. If the file to be read "all at once" exceeds that size, the file can be read, and every 1MB saved in a row of a dynamic array of strings, using the PUSH instruction for each portion read. In this way, it is possible to work with portions of a file. While the language certainly doesn't support strings in the traditional sense, relaxing the definition to mean any contiguous sequence of null-terminated bytes permits a reasonable facsimile.
This cat program eschews the simpler byte-by-byte approach ,[. It is not possible to specify encodings: the file is read as binary data on some system, the b flag is ignored and there's no difference between "r" and "rb" ; on others, it changes the way the "new lines" are treated, but this should not affect fread.
Memory map on Windows. In practice, it would be necessary to check for errors, and to take care of large files.
Also, this example is using a view on the whole file, but it's possible to create a smaller view. The core function slurp does the trick; you can specify an encoding as an optional second argument:. This works with text files, but fails with binary files that contain NUL characters. CMake truncates the string at the first NUL character, and there is no way to detect this truncation. The only way to read binary files is to use the HEX keyword to convert the entire file to a hexadecimal string.
The macro with-open-file could be passed :external-format :utf-8 on some implementations which it would pass on to open so that reading would occur by unicode character but file-length stream would continue to return the number of bytes, not characters, necessary for storing it. To get a string from a file, you need to explicitly decode the binary blob that is read. Currently only UTF-8 is supported by vu.
Two solutions in the FileReader namespace. Errors can be caught and turned into error strings via Erlang's :file. If an existing buffer is visiting the file, perhaps yet unsaved, it may be helpful to take its contents instead of re-reading the file. Euphoria cannot natively handle multibyte character encodings. It may have been implemented by now. Reading the entire source file in memory, then printing it. Here is a solution using the Windows API to create a memory map of a file.
It is used to print the source code of the program on the console. The encoding can be specified if necessary. Note: This code goes beyond simply specifying the file to open. It includes a dialog window that allows the user to select a text file to read. Depending on system memory, as many as 4. The file contents are placed in a convenient console window with automatic save as, copy and paste, select all and undo commands.
Of course, the programmer is free to code his own window and menu options. Go has good support for working with strings as UTF-8, but there is no requirement that strings be UTF-8 and in fact they can hold arbitrary data. ReadFile returns the contents of the file unaltered as a byte array. The conversion in the next line from byte array to string also makes no changes to the data.
In the example below sv will have an exact copy of the data in the file, without regard to encoding. Go also supports memory mapped files on OSes with a mmap syscall e. The following prints the contents of "file".
The included "build constraint" prevents this from being compiled on architectures known to lack syscall. Mmap , another source file with the opposite build constraint could use ioutil. ReadFile as above. Note that readFile is lazy. If you want to ensure the entire file is read in at once, before any other IO actions are run, try:. What about IO. I wanted to change the mode, which doesn't seem possible with IO. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. What's a reasonable way to read an entire text file as a single string?
Ask Question. Asked 10 years, 6 months ago. Active 3 months ago. Viewed 39k times. I am sure this is an easy one; I just couldn't find the answer immediately from Google. I know I could do this right? Or is that the way one would do it in Ruby? Improve this question. Dan Tao Dan Tao k 53 53 gold badges silver badges bronze badges.
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