1. "Preferences"-->"Settings" open a new window, then "Tools"-->"Build system"-->"New Build System"
2. Put this in:
{
"cmd": ["/usr/bin/python3", "-u", "$file"],
"file_regex": "^[ ]*File \"(...*?)\", line ([0-9]*)",
"selector": "source.python"
}
3. Save as "Python3.sublime-build" in "Packages/User/" folder.
4. Go to "Build system", change it to "Python3".
5. OK, everything is alright, press "Ctrl + B" running codes, have fun!
PS:
If you don't know where Python3 is, just open Terminal, inputting "which python3" + Enter, then you'll get Python3 path if you already installed.
