str={"USD":{"last":352.49,"bid":352.49,"ask":353.6,
            "high":358.75,"low":349.34,"volume":6678.7783}.....

colvector=[352.49,352.49,353.6,358.75,349.34,6678.7783]

fmt=['{"USD":{"last": "%f", "bid": "%f", "ask": "%f",
              "high": "%f", "low": "%f", "volume": "%f"}...

s = 'str={"USD":{"last":352.49,"bid":352.49,"ask":353.6,"high":358.75,"low":349.34,"volume":6678.7783}.';

result = cellfun(@str2num, regexp(s, 'd+(.d+)?', 'match'));

result =

  1.0e+003 *

    0.3525    0.3525    0.3536    0.3588    0.3493    6.6788