to sweep open your wallet and from the menu select:
Wallet > Private keys > Sweep
then paste the full private keys there and then click the "Address button" or manually paste a new address to give electrum an address from your wallet to send the funds to. and then click "Sweep"
I am not really sure about sweep but I guess it will transfer bitcoin into another wallet.
Sweeping private keys means to send all the bitcoins they control to an existing address in your wallet
I want to export as well but don't know where to find it, and I find out it doesn't support this feature. I am using electrum 2.8.3
In Electrum 2.0, you cannot import private keys in a wallet that has a seed. You should sweep them instead.
Anyway, you cannot "sweep" a private key unless it contains some bitcoins (as it creates an onchain transaction that will require a fee to be paid!)... so you need to figure out which of your addresses have coins in them, and sweep just those keys!
You can see which addresses have coins by going to the 'Coins' tab (NOTE: you may need to use "Wallet -> Coins", if you can't see a 'Coins' tab)
Yes, I would like to give it a shot, just try to sweep into the same wallet.
Thanks for your answer, I will check which one of those addresses contain bitcoin and try it later.