Visualize the character codes in a string

charcodes = ToCharacterCode["this is a string."]

{116, 104, 105, 115, 32, 105, 115, 32, 97, 32, 115, 116, 114, 105, 110, 103, 46}

ListPlot[charcodes, Filling -> Axis]

-Graphics-

FromCharacterCode[charcodes]

this is a string.