This is the 16298th most frequent Turkish word.
yaptıklarından
"From what they/you have done."
In this sentence, "yaptıklarından" refers to actions already performed by them, emphasizing the reason for the thanks.
Yaptıklarından dolayı onlara teşekkür ettim.
I thanked them for what they have done.
Here, "yaptıklarından" expresses the actions completed by the individual, tying them to the feeling of regret.
Yaptıklarından pişman olmuş olabilir.
They might regret what they have done.
In this example, "yaptıklarından" is used to indicate actions taken as the subject of the discussion in answering.