Python read-write file mode

1. R to open a read-only file, the file must exist.
2. r+ open a writable file, the file must exist.
3, W open only write files, if the file exists, the file length is clear to 0, that is, the contents of the file will disappear. If the file does not exist, the file is created.
4, w+ Open can read and write files, if the file exists, the file length is clear to zero, that is, the contents of the file will disappear. If the file does not exist, the file is created.
5. A write-only file is opened in an additional way. If the file does not exist, the file will be created, and if the file exists, the data written will be added to the end of the file, that is, the original content of the file will be retained.
6. A + opens a read-write file in an additional way. If the file does not exist, the file will be created, and if the file exists, the data written will be added to the end of the file, that is, the original content of the file will be retained.
7, the above morphological string can be added a B character, such as RB, w+b or ab+ combination, add B character used to tell the library to open the file is a binary file, rather than a plain text file. However, in a POSIX system, including Linux ignores the character.

Python read-write file mode