The History Behind the Definition of a 'String'

Question

I have never thought about until recently, but I\'m not sure why we call strings strings. I am a .NET programmer, but I believe the concept of strings exist in

Answer 1

A string is a sequence of discrete objects (usually char).

Given that, I would probably venture a guess that it may have to do with a metaphor related to "string of pearls". Each bead on the string is a single character.

Answer 2

From this reference:

The 1971 OED (p. 3097) quotes an 1891 Century Dictionary on a source in the Milwaukee Sentinel of 11 Jan. 1898 (section 3, p. 1) to the effect that this is a compositor's term. Printers would paste up the text that they had generated in a long strip of characters. (Presumably, they were paid by the foot, not by the word!) The quote says that it was not unusual for compositors to create more than 1500 (characters?) per hour.

Answer 3

From searching through the ACM bibliography it seems the word string acquired its meaning in computer science during the 1960s. At the beginning a string is a general kind of sequence or list, e.g. A command language for handling strings of symbols from 1958.

This article explicitly mentions "character strings" in 1964.

Unfortunately I can't access the full texts, which are behind a toll booth.

Answer 4

The word was originally used to differentiate between a set of values to which the particular order of elements doesn't matter (for instance, a set of random samples of measurements) and another that could only have its meaning preserved when the order is also preserved. Originally a string could be a set of any kind of values, but since in the post-mainframe era a string of characters is by far the most common kind, the fact that the values are characters became a "default".

Answer 5

I had guessed that "string" was in use by mathematicians long before its adoption in programming languages. Turing machines effectively operate on strings. Turing may not have used the term, but it is used everywhere in automata textbooks, going back decades.

The earliest reference I could find was a fragment in Google books of a 1944 article "Recursively enumerable sets of positive integers and their decision problems" by logician Emil Post in Bulletin of the AMS. Fortunately, AMS provides online archives of complete articles free for download. Here is a link: http://www.ams.org/journals/bull/1944-50-05/S0002-9904-1944-08111-1/S0002-9904-1944-08111-1.pdf

I think there is little doubt that he is using "string" in the conventional sense used in computer science. P. 286 "For working purposes, we in- troduce the letter b, and consider "strings" of 1's and b's such as 11b1bb1. An operation on such strings such as "b1bP produces P1bb1" we term a normal operation. This particular normal operation is ap- plicable only to strings starting with b1b, and the derived string is then obtained from the given string by first removing the initial b1b, and then tacking on 1bb1 at the end. Thus b1bb becomes b1bb1."

Answer 6

I suspect it's because string originally meant just a sequence of data values: "I'll just string these together" etc. These values didn't have to be characters. One very common use for this general concept happened to be a sequence of characters, and this took over as the general meaning of the word.