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Strings can be concatenated using matrix notation (see Strings, Character Arrays) which is often the most natural method. For example:
fullname = [fname ".txt"]; email = ["<" user "@" domain ">"];
In each case it is easy to see what the final string will look like. This method is also the most efficient. When using matrix concatenation the parser immediately begins joining the strings without having to process the overhead of a function call and the input validation of the associated function.
The newline
function can be used to join strings such that they appear
as multiple lines of text when displayed.
Return the character corresponding to a newline.
This is equivalent to "\n"
.
Example Code
joined_string = [newline "line1" newline "line2"] ⇒ line1 line2
In addition, there are several other functions for concatenating string
objects which can be useful in specific circumstances: char
,
strvcat
, strcat
, and cstrcat
. Finally, the general
purpose concatenation functions can be used: see cat,
horzcat, and vertcat.
cstrcat
convert numerical input into character data by taking the corresponding UTF-8
character for each element (or multi-byte sequence), as in the following
example:
char ([98, 97, 110, 97, 110, 97]) ⇒ banana
For conversion between locale encodings and UTF-8, see unicode2native and native2unicode.
char
and strvcat
concatenate vertically, while strcat
and cstrcat
concatenate
horizontally. For example:
char ("an apple", "two pears") ⇒ an apple two pears
strcat ("oc", "tave", " is", " good", " for you") ⇒ octave is good for you
char
generates an empty row in the output
for each empty string in the input. strvcat
, on the other hand,
eliminates empty strings.
char ("orange", "green", "", "red") ⇒ orange green red
strvcat ("orange", "green", "", "red") ⇒ orange green red
cstrcat
also accept cell
array data (see Cell Arrays). char
and
strvcat
convert cell arrays into character arrays, while strcat
concatenates within the cells of the cell arrays:
char ({"red", "green", "", "blue"}) ⇒ red green blue
strcat ({"abc"; "ghi"}, {"def"; "jkl"}) ⇒ { [1,1] = abcdef [2,1] = ghijkl }
strcat
removes trailing white space in the arguments (except
within cell arrays), while cstrcat
leaves white space untouched. Both
kinds of behavior can be useful as can be seen in the examples:
strcat (["dir1";"directory2"], ["/";"/"], ["file1";"file2"]) ⇒ dir1/file1 directory2/file2
cstrcat (["thirteen apples"; "a banana"], [" 5$";" 1$"]) ⇒ thirteen apples 5$ a banana 1$
Note that in the above example for cstrcat
, the white space originates
from the internal representation of the strings in a string array
(see Character Arrays).
Create a string array from one or more numeric matrices, character matrices, or cell arrays.
Arguments are concatenated vertically. The returned values are padded with blanks as needed to make each row of the string array have the same length. Empty input strings are significant and will concatenated in the output.
For numerical input, each element is converted to the corresponding ASCII character. A range error results if an input is outside the ASCII range (0-255).
For cell arrays, each element is concatenated separately. Cell arrays
converted through char
can mostly be converted back with
cellstr
. For example:
char ([97, 98, 99], "", {"98", "99", 100}, "str1", ["ha", "lf"]) ⇒ ["abc " " " "98 " "99 " "d " "str1" "half"]
Create a character array from one or more numeric matrices, character matrices, or cell arrays.
Arguments are concatenated vertically. The returned values are padded with
blanks as needed to make each row of the string array have the same length.
Unlike char
, empty strings are removed and will not appear in the
output.
For numerical input, each element is converted to the corresponding ASCII character. A range error results if an input is outside the ASCII range (0-255).
For cell arrays, each element is concatenated separately. Cell arrays
converted through strvcat
can mostly be converted back with
cellstr
. For example:
strvcat ([97, 98, 99], "", {"98", "99", 100}, "str1", ["ha", "lf"]) ⇒ ["abc " "98 " "99 " "d " "str1" "half"]
Return a string containing all the arguments concatenated horizontally.
If the arguments are cell strings, strcat
returns a cell string
with the individual cells concatenated. For numerical input, each element
is converted to the corresponding ASCII character. Trailing white space
for any character string input is eliminated before the strings are
concatenated. Note that cell string values do not have
whitespace trimmed.
For example:
strcat ("|", " leading space is preserved", "|") ⇒ | leading space is preserved|
strcat ("|", "trailing space is eliminated ", "|") ⇒ |trailing space is eliminated|
strcat ("homogeneous space |", " ", "| is also eliminated") ⇒ homogeneous space || is also eliminated
s = [ "ab"; "cde" ]; strcat (s, s, s) ⇒ "ababab " "cdecdecde"
s = { "ab"; "cd " }; strcat (s, s, s) ⇒ { [1,1] = ababab [2,1] = cd cd cd }
Next: Splitting and Joining Strings, Previous: Common String Operations, Up: String Operations [Contents][Index]