from c++ to pyqt4 QByteArray

[alrawab]

is it your intention that this pointer

const char* opq = sequence.data() +55;

be invalid? It points to memory outside of the string - you are later reading random memory addresses...

This also looks nonsensical

for(int i=0;i< sequence.size(); i++) {
  char rdf= opq[i];
  char cl = map.at(rdf)
}

for(int i=0;i< sequence.size(); i++) {
  char rdf= opq[i];
  char cl = map.at(rdf)
}

To copy to clipboard, switch view to plain text mode 

i know im concern the conversion and 55 is an example for any int
this is the real code
const QByteArray& sequence = detView->getSequenceContext()->getSequenceData();
const char* seq = sequence.data() + detView->getVisibleRange().startPos;

DNATranslation* complTrans = detView->getComplementTT();
QByteArray map = complTrans->getOne2OneMapper();
int y = getTextY(complementLine);
for(int i=0;i< visibleRange.len; i++) {
char nucl = seq[i];
char complNucl = map.at(nucl);
}