Is a Lumix G1 a bridge camera?

I feel that it doesn't have certain settings (can't remember from the top of my head) than a canon or a nikon has and many guides have said this is a good beginners' camera?

No, it is an entry level dSLR that uses interchangeable lenses

Bridge cameras are advanced P&S cameras that have a permanently attached lens

The G1 is a compact system camera (CSC), also known as a mirrorless interchangeable lens camera (MILC), also known as a electronic viewfinder interchangeable lens (EVIL) camera. It therefore has a relatively large sensor (much larger than a bridge) and a selection of lenses, each of which will do a specific job.

The CSC/MILC/EVIL is mainly targeted as a complementary camera to photographers who demand something smaller than their regular DSLR, and as compromise for consumer users who want compact performance at the sacrifice of versatility.

I would say it's an expensive way to go if you're learning photography, the cameras are expensive for the level of performance they deliver. The lens selection is limited if you demand autofocus. Of course if you select older manual focus lenses and adapt them then your options are unbelievably broad.

Best compromise, I would still think is the Canon EF system. It's not expensive to get an entry level camera, and you have an extremely good selection of autofocus lenses.