File Input/Output
You read from a file into memory and write from memory to a file.
Before reading or writing a file, you need to open it:
fileobj = open(filename, mode)
mode is a string indicating the file’s type and what you want to do with it.
The first letter of mode indicates the operation:
- r means read
- w means write. If the file does not exist, it’s created. If the file does exist, it’s overwritten
- x means write, but only if the file does not already exist.
- a means append (write after the end) if the file exists.
The second letter of mode is the file’s type:
- t (or nothing) means text.
- b means binary
Before reading or writing a file, you need to open it. After opening the file, you call functions to read and write data, and you need to close the file at last.