There's very little context in your question.
I'll make assumptions :
1- You're doing classification
2- You have 2 classes
3- The float vector has probabilities of the data point being positive
In that case you should threshold the probability predictions to 0 and 1 (for ex. with threshold=0.5), then make sure the 0/1 vector is of int type. Then sklearn.metrics.accuracy_score should work, it will then compare your 0/1 predictions with 0/1 ground truth labels, and calculate accuracy out of them. I hope that helps.