Erlang parse text file




















The functions are kept for backward compatibility, but are not recommended. They will be deprecated in a future release. Returns a string, where String is centered in the string and surrounded by blanks or Character. The resulting string has length Number.

This function is obsolete. Returns a string consisting of Number characters Character. Optionally, the string can end with string Tail. Returns the index of the first occurrence of Character in String.

Returns 0 if Character does not occur. Concatenates String1 and String2 to form a new string String3 , which is returned. Returns a string containing String repeated Number times. Returns the length of the maximum initial segment of String , which consists entirely of characters not from Chars. Returns a string with the elements of StringList separated by the string in Separator. Returns String with the length adjusted in accordance with Number. The left margin is fixed. Returns the index of the last occurrence of Character in String.

The right margin is fixed. Returns the position where the last occurrence of SubString begins in String. Returns 0 if SubString does not exist in String.

Returns the length of the maximum initial segment of String , which consists entirely of characters from Chars. Returns the position where the first occurrence of SubString begins in String. Returns a string, where leading or trailing, or both, blanks or a number of Character have been removed. Direction , which can be left , right , or both , indicates from which direction blanks are to be removed. Returns a substring of String , starting at position Start to the end of the string, or to and including position Stop.

Returns a substring of String , starting at position Start , and ending at the end of the string or at length Length. Returns the word in position Number of String. Words are separated by blanks or Character s.

The specified string or character is case-converted. Returns a list of tokens in String , separated by the characters in SeparatorList. Notice that, as shown in this example, two or more adjacent separator characters in String are treated as one.

This can be useful in particular during the early boot stage when the file server is not yet registered, to still be able to delete local files. A component of the filename is not a directory. In a future release, a bad type for argument Filename will probably generate an exception.

Reads and evaluates Erlang expressions, separated by '. The result of the evaluation is not returned; any expression sequence in the file must be there for its side effect. An error occurred when interpreting the Erlang expressions in the file. Given the error reason returned by any function in this module, returns a descriptive string of the error in English.

In rare circumstances, this function can fail on Unix. It can occur if read permission does not exist for the parent directories of the current directory. Drive is to be of the form " Letter : ", for example, "c:". Lists all files in a directory, except files with raw filenames. Filenames is a list of the names of all the files in the directory. The names are not sorted.

Missing search or write permissions for Dir or one of its parent directories. Lists all the files in a directory, including files with raw filenames. Tries to create directory Dir. Missing parent directories are not created. Makes a hard link from Existing to New on platforms supporting links Unix and Windows. Missing read or write permissions for the parent directories of Existing or New. Creates a symbolic link New to the file or directory Existing on platforms supporting symbolic links most Unix systems and Windows, beginning with Vista.

Existing does not need to exist. Returns the filename encoding mode. If it is latin1 , the system translates no filenames. Opens file File in the mode determined by Modes , which can contain one or more of the following options:. The file is opened for writing.

It is created if it does not exist. If the file exists and write is not combined with read , the file is truncated. Every write operation to a file opened with append takes place at the end of the file. Do not depend on this option unless you know that the file system supports it in general, local file systems are safe.

Allows faster access to a file, as no Erlang process is needed to handle the file. However, a file opened in this way has the following limitations:. The functions in the io module cannot be used, as they can only talk to an Erlang process. A remote Erlang file server cannot be used.

The computer on which the Erlang node is running must have access to the file system directly or through NFS. Then all buffered data is written in one operating system call. The purpose of this option is to increase performance by reducing the number of operating system calls.

Activates read data buffering. Makes it possible to read or write gzip compressed files. Option compressed must be combined with read or write , but not both. Makes the file perform automatic translation of characters to and from a specific Unicode encoding. Depending on the encoding, different methods of reading and writing data is preferred. The default encoding of latin1 implies using this module file for reading and writing data as the interfaces provided here work with byte-oriented data.

The default encoding. If module io 3 is used for writing, the file can only cope with Unicode characters up to code point the ISO Latin-1 range. Characters are translated to and from UTF-8 encoding before they are written to or read from the file. The file is best read with the functions in the Unicode aware module io 3.

Bytes written to the file by any means are translated to UTF-8 encoding before being stored on the disk file. So a file can be analyzed in latin1 encoding for, for example, a BOM, positioned beyond the BOM and then be set for the right encoding before further reading.

For functions identifying BOMs, see module unicode 3. File must be iodata. Returns an fd , which lets module file operate on the data in-memory as if it is a file. However, be aware that the exact semantics of this flag differ from platform to platform. For example, none of Linux or Windows guarantees that all file metadata are also written before the call returns. For precise semantics, check the details of your platform documentation.

The file is opened in the requested mode. IoDevice is a reference to the file. IoDevice is really the pid of the process that handles the file. This process monitors the process that originally opened the file the owner process.

If the owner process terminates, the file is closed and the process itself terminates too. While this function can be used to open any file, we recommend against using it for NFS-mounted files, FIFOs, devices, or similar since they can cause IO threads to hang forever. If your application needs to interact with these kinds of files we recommend breaking out those parts to a port program instead.

This is still allowed for reasons of backwards compatibility, but is not to be used for new code. Missing permission for reading the file or searching one of the parent directories.

A component of the filename is not a directory, or the filename itself is not a directory if directory mode was specified. There is no space left on the device if write access was specified. Searches the path Path a list of directory names until the file Filename is found. If Filename is an absolute filename, Path is ignored. Then reads Erlang terms, separated by '. The file is successfully read. FullName is the full name of the file. The file cannot be found in any of the directories in Path.

The encoding of Filename can be set by a comment as described in epp 3. Then reads and evaluates Erlang expressions, separated by '. The result of evaluation is not returned; any expression sequence in the file must be there for its side effect. The file is read and evaluated. Then opens the file in the mode determined by Modes. IoDevice is a reference to the file and FullName is the full name of the file.

FullName is the full name of the file and Value the value of the last expression. If the file server of this node is not a slave, the file was opened by the file server of this node this implies that Pid must be a local pid and the file is not closed. Filename is the filename in flat string format.

Sets the position of the file referenced by IoDevice to Location. Location is one of the following:. Find centralized, trusted content and collaborate around the technologies you use most. Connect and share knowledge within a single location that is structured and easy to search. However, the file contains some non-English characters in strings. So, when I read the file, those strings are displayed as a list of numbers.

The result is that it gets saved as a list of integers and therefore when I try to do things like ets:lookup it also gives me back a list on the shell. The basic principle you have to keep in your mind is that you are seeing Unicode already, all the time. Unicode is strings of numbers, and without any special instruction the shell will just show you that: strings of numbers.

Hopefully this gets you closer to a solution. Whatever the case, I strongly recommend that every Erlanger read the " Using Unicode in Erlang " part of the docs. In Erlang, all strings are lists of numbers.

If you're writing the strings back to a file or comparing them in memory, you should be OK to treat all your strings the same. The foreign chars will be ugly to look at when debugging, but they should read and write correctly.

I'm not sure if things are as easy if you need to store the strings in an external database or send them over the wire to some other service.

At that point, you'll probably need to handle encoding yourself. This means that if your file is UTF8 format and you're using Erlang 17, everything will work great! Stack Overflow for Teams — Collaborate and share knowledge with a private group.

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