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Octave strings are character arrays. Strings of different lengths can't go in a regular array — use cell arrays.

Strings

s = "hello";
double_s = double(s)        %% [104 101 108 108 111] (ASCII codes)
len = length(s)              %% 5
upper = upper(s)             %% "HELLO"
rev = fliplr(s)              %% "olleh"
s(1)                          %% "h" (1-indexed!)
s(2:4)                        %% "ell"

String concatenation

["hello", " ", "world"]      %% "hello world"  (regular array concat)
strcat("hello", " world")    %% beware: strcat strips trailing spaces!
sprintf("%s %s", a, b)       %% safer

sprintf and printf

sprintf("%d items, $%.2f each", 3, 9.99)
%% prints "3 items, $9.99" — same format syntax as C

printf("%s scored %d (%.1f%%)\n", "Ada", 95, 95.0)
%% writes to stdout

strsplit / strjoin

parts = strsplit("a,b,c,d", ",")    %% {"a", "b", "c", "d"} — cell array
strjoin({"a", "b", "c"}, "-")        %% "a-b-c"

Cell arrays — heterogeneous

Regular [] arrays must be all-same-size. Cell arrays {} can hold anything:

stuff = {"Ada", 36, [1 2 3]}
stuff{1}                       %% "Ada"
stuff{2}                       %% 36
stuff{3}                       %% [1 2 3]

Note {} for ACCESS too — stuff{i} gets the contents, stuff(i) returns a 1-element cell array.

Common string funcs

strtrim("  hi  ")              %% "hi"
strrep("hello", "l", "L")     %% "heLLo"
strfind("banana", "an")         %% [2 4]
regexp("abc123", "\\d+", "match")   %% {"123"}
strcmp("foo", "foo")            %% true (1)
str2num("42")                    %% 42
num2str(42)                      %% "42"

Multi-line strings

s = sprintf("line 1\nline 2\nline 3")

No triple-quote literals — use sprintf or string concatenation.