Python open typeerror an integer is required

python open typeerror an integer is required

TypeErrors are a common type of error in Python. They occur when you try to apply a function on a value of the wrong type. An “'int' object is. The following snippet produces "TypeError: an integer is required (got type bytes)" with Python 3.8. Code snippet from goto import with_goto. Because you did from os import *, you are (accidenally) using os.open, which indeed requires an integer flag instead of a textual "r" or "w". Take out that.

Python open typeerror an integer is required - agree, very

PROT_READ, access=ACCESS_DEFAULT[, offset])

(Unix version) Maps length bytes from the file specified by the file descriptor fileno, and returns a mmap object. If length is , the maximum length of the map will be the current size of the file when is called.

flags specifies the nature of the mapping. creates a private copy-on-write mapping, so changes to the contents of the mmap object will be private to this process, and creates a mapping that’s shared with all other processes mapping the same areas of the file. The default value is . Some systems have additional possible flags with the full list specified in MAP_* constants.

prot, if specified, gives the desired memory protection; the two most useful values are and , to specify that the pages may be read or written. prot defaults to .

access may be specified in lieu of flags and prot as an optional keyword parameter. It is an error to specify both flags, prot and access. See the description of access above for information on how to use this parameter.

offset may be specified as a non-negative integer offset. mmap references will be relative to the offset from the beginning of the file. offset defaults to 0. offset must be a multiple of which is equal to on Unix systems.

To ensure validity of the created memory mapping the file specified by the descriptor fileno is internally automatically synchronized with the physical backing store on macOS.

This example shows a simple way of using :

importmmap# write a simple example filewithopen("hello.txt","wb")asf:f.write(b"Hello Python!\n")withopen("hello.txt","r+b")asf:# memory-map the file, size 0 means whole filemm=mmap.mmap(f.fileno(),0)# read content via standard file methodsprint(mm.readline())# prints b"Hello Python!\n"# read content via slice notationprint(mm[:5])# prints b"Hello"# update content using slice notation;# note that new content must have same sizemm[6:]=b" world!\n"# ... and read again using standard file methodsmm.seek(0)print(mm.readline())# prints b"Hello world!\n"# close the mapmm.close()

can also be used as a context manager in a statement:

importmmapwithmmap.mmap(-1,13)asmm:mm.write(b"Hello world!")

New in version 3.2: Context manager support.

The next example demonstrates how to create an anonymous map and exchange data between the parent and child processes:

importmmapimportosmm=mmap.mmap(-1,13)mm.write(b"Hello world!")pid=os.fork()ifpid==0:# In a child processmm.seek(0)print(mm.readline())mm.close()

Raises an auditing event with arguments , , , .

Memory-mapped file objects support the following methods:

()¶

Closes the mmap. Subsequent calls to other methods of the object will result in a ValueError exception being raised. This will not close the open file.

if the file is closed.

(sub[, start[, end]])¶

Returns the lowest index in the object where the subsequence sub is found, such that sub is contained in the range [start, end]. Optional arguments start and end are interpreted as in slice notation. Returns on failure.

([offset[, size]])¶

Flushes changes made to the in-memory copy of a file back to disk. Without use of this call there is no guarantee that changes are written back before the object is destroyed. If offset and size are specified, only changes to the given range of bytes will be flushed to disk; otherwise, the whole extent of the mapping is flushed. offset must be a multiple of the or .

is returned to indicate success. An exception is raised when the call failed.

Changed in version 3.8: Previously, a nonzero value was returned on success; zero was returned on error under Windows. A zero value was returned on success; an exception was raised on error under Unix.

(option[, start[, length]])¶

Send advice option to the kernel about the memory region beginning at start and extending length bytes. option must be one of the MADV_* constants available on the system. If start and length are omitted, the entire mapping is spanned. On some systems (including Linux), start must be a multiple of the .

Availability: Systems with the system call.

(dest, src, count

Copy the count bytes starting at offset src to the destination index dest. If the mmap was created with , then calls to move will raise a exception.

([n])¶

Return a containing up to n bytes starting from the current file position. If the argument is omitted, or negative, return all bytes from the current file position to the end of the mapping. The file position is updated to point after the bytes that were returned.

Changed in version 3.3: Argument can be omitted or .

()¶

Returns a byte at the current file position as an integer, and advances the file position by 1.

()¶

Returns a single line, starting at the current file position and up to the next newline. The file position is updated to point after the bytes that were returned.

(newsize

Resizes the map and the underlying file, if any. If the mmap was created with or , resizing the map will raise a exception.

(sub[, start[, end]])¶

Returns the highest index in the object where the subsequence sub is found, such that sub is contained in the range [start, end]. Optional arguments start and end are interpreted as in slice notation. Returns on failure.

(pos[, whence])¶

Set the file’s current position. whence argument is optional and defaults to or (absolute file positioning); other values are or (seek relative to the current position) and or (seek relative to the file’s end).

()¶

Return the length of the file, which can be larger than the size of the memory-mapped area.

()¶

Returns the current position of the file pointer.

(bytes

Write the bytes in bytes into memory at the current position of the file pointer and return the number of bytes written (never less than , since if the write fails, a will be raised). The file position is updated to point after the bytes that were written. If the mmap was created with , then writing to it will raise a exception.

Changed in version 3.6: The number of bytes written is now returned.

(byte

Write the integer byte into memory at the current position of the file pointer; the file position is advanced by . If the mmap was created with , then writing to it will raise a exception.

MADV_* Constants¶

These options can be passed to . Not every option will be present on every system.

Availability: Systems with the madvise() system call.

MAP_* Constants¶

These are the various flags that can be passed to . Note that some options might not be present on some systems.

Changed in version 3.10: Added MAP_POPULATE constant.