VIM command to save the read only opened file with sudo permission

Most of the times, we get stuck on saving a vim editor contents as we would have been editing in a read-only mode. Normally when I face this situation, I use to exit the vim editor and re-open it with sudo permission and start my work all again. This command help me today to get rid of this pain. Yup, saving the read-only mode opened files with sudo permission with in the same shell. :w !sudo tee %