Uniform sequence of IEEE double-precision numbers.
    Binary data format.

Import and Export

  • Import["file","Real64"] imports any file as 64-bit IEEE double-precision numbers, returning a packed array of real numbers.
  • Export["file",list,"Real64"] exports a list of real numbers to file.
  • Import["file",{"Real64",elem}] or Import["file",elem ] imports the specified element from file.
  • Import["file",{"Real64",{elem1,elem2,}}] imports multiple elements.
  • See the reference pages for full general information on Import and Export.
  • ImportString and ExportString support the Real64 format.


  • General Import elements:
  • "Elements" elements and options available in this file
    "Rules"full rules for each element and option
    "Options"rules for options, properties, and settings
  • Data representation element:
  • "Data"list of real numbers
  • By default, Import and Export use the "Data" element.
  • Import["file",{"Real64",n}] reads the n^(th) double-precision number from file.
  • Import returns Infinity for IEEE "infinity", and Indeterminate for IEEE "notanumber".
  • Trailing bytes are ignored if the size of the imported file is not a multiple of the data size.


  • General option:
  • ByteOrdering-1what byte ordering to use
  • Import option:
  • "HeaderBytes"0how many bytes to skip at the beginning of the file


Basic Examples  (1)

Convert a list of integers and reals to IEEE double-precision numbers:

Click for copyable input

Convert the previous result back to Wolfram Language numbers:

Click for copyable input

See Also

"Binary"  "Bit"  "Byte"  "Character8"  "Character16"  "Integer8"  "Integer16"  "Integer24"  "Integer32"  "Integer64"  "Integer128"  "UnsignedInteger8"  "UnsignedInteger16"  "UnsignedInteger32"  "UnsignedInteger64"  "UnsignedInteger128"  "Real32"  "Real128"  "Complex64"  "Complex128"  "Complex256"  "String"

Introduced in 2004
| Updated in 2007