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<a name="Concatenating-Strings"></a>
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<p>
Next: <a href="Converting-Numerical-Data-to-Strings.html#Converting-Numerical-Data-to-Strings" accesskey="n" rel="next">Converting Numerical Data to Strings</a>, Up: <a href="Creating-Strings.html#Creating-Strings" accesskey="u" rel="up">Creating Strings</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Concatenating-Strings-1"></a>
<h4 class="subsection">5.3.1 Concatenating Strings</h4>
<p>Strings can be concatenated using matrix notation
(see <a href="Strings.html#Strings">Strings</a>, <a href="Character-Arrays.html#Character-Arrays">Character Arrays</a>) which is often the most natural
method. For example:
</p>
<div class="example">
<pre class="example">fullname = [fname ".txt"];
email = ["<" user "@" domain ">"];
</pre></div>
<p>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.
</p>
<p>Nevertheless, there are several other functions for concatenating string
objects which can be useful in specific circumstances: <code>char</code>,
<code>strvcat</code>, <code>strcat</code>, and <code>cstrcat</code>. Finally, the general
purpose concatenation functions can be used: see <a href="Rearranging-Matrices.html#XREFcat">cat</a>,
<a href="Rearranging-Matrices.html#XREFhorzcat">horzcat</a>, and <a href="Rearranging-Matrices.html#XREFvertcat">vertcat</a>.
</p>
<ul>
<li> All string concatenation functions except <code>cstrcat</code>
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:
<div class="example">
<pre class="example">char ([98, 97, 110, 97, 110, 97])
⇒ banana
</pre></div>
<p>For conversion between locale encodings and UTF-8, see
<a href="String-Conversions.html#XREFunicode2native">unicode2native</a> and
<a href="String-Conversions.html#XREFnative2unicode">native2unicode</a>.
</p>
</li><li> <code>char</code> and <code>strvcat</code>
concatenate vertically, while <code>strcat</code> and <code>cstrcat</code> concatenate
horizontally. For example:
<div class="example">
<pre class="example">char ("an apple", "two pears")
⇒ an apple
two pears
</pre><pre class="example">
</pre><pre class="example">strcat ("oc", "tave", " is", " good", " for you")
⇒ octave is good for you
</pre></div>
</li><li> <code>char</code> generates an empty row in the output
for each empty string in the input. <code>strvcat</code>, on the other hand,
eliminates empty strings.
<div class="example">
<pre class="example">char ("orange", "green", "", "red")
⇒ orange
green
red
</pre><pre class="example">
</pre><pre class="example">strvcat ("orange", "green", "", "red")
⇒ orange
green
red
</pre></div>
</li><li> All string concatenation functions except <code>cstrcat</code> also accept cell
array data (see <a href="Cell-Arrays.html#Cell-Arrays">Cell Arrays</a>). <code>char</code> and
<code>strvcat</code> convert cell arrays into character arrays, while <code>strcat</code>
concatenates within the cells of the cell arrays:
<div class="example">
<pre class="example">char ({"red", "green", "", "blue"})
⇒ red
green
blue
</pre><pre class="example">
</pre><pre class="example">strcat ({"abc"; "ghi"}, {"def"; "jkl"})
⇒
{
[1,1] = abcdef
[2,1] = ghijkl
}
</pre></div>
</li><li> <code>strcat</code> removes trailing white space in the arguments (except
within cell arrays), while <code>cstrcat</code> leaves white space untouched. Both
kinds of behavior can be useful as can be seen in the examples:
<div class="example">
<pre class="example">strcat (["dir1";"directory2"], ["/";"/"], ["file1";"file2"])
⇒ dir1/file1
directory2/file2
</pre><pre class="example">
cstrcat (["thirteen apples"; "a banana"], [" 5$";" 1$"])
⇒ thirteen apples 5$
a banana 1$
</pre></div>
<p>Note that in the above example for <code>cstrcat</code>, the white space originates
from the internal representation of the strings in a string array
(see <a href="Character-Arrays.html#Character-Arrays">Character Arrays</a>).
</p></li></ul>
<a name="XREFchar"></a><dl>
<dt><a name="index-char"></a><em></em> <strong>char</strong> <em>(<var>x</var>)</em></dt>
<dt><a name="index-char-1"></a><em></em> <strong>char</strong> <em>(<var>x</var>, …)</em></dt>
<dt><a name="index-char-2"></a><em></em> <strong>char</strong> <em>(<var>s1</var>, <var>s2</var>, …)</em></dt>
<dt><a name="index-char-3"></a><em></em> <strong>char</strong> <em>(<var>cell_array</var>)</em></dt>
<dd><p>Create a string array from one or more numeric matrices, character
matrices, or cell arrays.
</p>
<p>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.
</p>
<p>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).
</p>
<p>For cell arrays, each element is concatenated separately. Cell arrays
converted through <code>char</code> can mostly be converted back with
<code>cellstr</code>. For example:
</p>
<div class="example">
<pre class="example">char ([97, 98, 99], "", {"98", "99", 100}, "str1", ["ha", "lf"])
⇒ ["abc "
" "
"98 "
"99 "
"d "
"str1"
"half"]
</pre></div>
<p><strong>See also:</strong> <a href="#XREFstrvcat">strvcat</a>, <a href="Cell-Arrays-of-Strings.html#XREFcellstr">cellstr</a>.
</p></dd></dl>
<a name="XREFstrvcat"></a><dl>
<dt><a name="index-strvcat"></a><em></em> <strong>strvcat</strong> <em>(<var>x</var>)</em></dt>
<dt><a name="index-strvcat-1"></a><em></em> <strong>strvcat</strong> <em>(<var>x</var>, …)</em></dt>
<dt><a name="index-strvcat-2"></a><em></em> <strong>strvcat</strong> <em>(<var>s1</var>, <var>s2</var>, …)</em></dt>
<dt><a name="index-strvcat-3"></a><em></em> <strong>strvcat</strong> <em>(<var>cell_array</var>)</em></dt>
<dd><p>Create a character array from one or more numeric matrices, character
matrices, or cell arrays.
</p>
<p>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 <code>char</code>, empty strings are removed and will not appear in the
output.
</p>
<p>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).
</p>
<p>For cell arrays, each element is concatenated separately. Cell arrays
converted through <code>strvcat</code> can mostly be converted back with
<code>cellstr</code>. For example:
</p>
<div class="example">
<pre class="example">strvcat ([97, 98, 99], "", {"98", "99", 100}, "str1", ["ha", "lf"])
⇒ ["abc "
"98 "
"99 "
"d "
"str1"
"half"]
</pre></div>
<p><strong>See also:</strong> <a href="#XREFchar">char</a>, <a href="#XREFstrcat">strcat</a>, <a href="#XREFcstrcat">cstrcat</a>.
</p></dd></dl>
<a name="XREFstrcat"></a><dl>
<dt><a name="index-strcat"></a><em></em> <strong>strcat</strong> <em>(<var>s1</var>, <var>s2</var>, …)</em></dt>
<dd><p>Return a string containing all the arguments concatenated
horizontally.
</p>
<p>If the arguments are cell strings, <code>strcat</code> 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 <strong>not</strong> have
whitespace trimmed.
</p>
<p>For example:
</p>
<div class="example">
<pre class="example">strcat ("|", " leading space is preserved", "|")
⇒ | leading space is preserved|
</pre></div>
<div class="example">
<pre class="example">strcat ("|", "trailing space is eliminated ", "|")
⇒ |trailing space is eliminated|
</pre></div>
<div class="example">
<pre class="example">strcat ("homogeneous space |", " ", "| is also eliminated")
⇒ homogeneous space || is also eliminated
</pre></div>
<div class="example">
<pre class="example">s = [ "ab"; "cde" ];
strcat (s, s, s)
⇒
"ababab "
"cdecdecde"
</pre></div>
<div class="example">
<pre class="example">s = { "ab"; "cd " };
strcat (s, s, s)
⇒
{
[1,1] = ababab
[2,1] = cd cd cd
}
</pre></div>
<p><strong>See also:</strong> <a href="#XREFcstrcat">cstrcat</a>, <a href="#XREFchar">char</a>, <a href="#XREFstrvcat">strvcat</a>.
</p></dd></dl>
<a name="XREFcstrcat"></a><dl>
<dt><a name="index-cstrcat"></a><em></em> <strong>cstrcat</strong> <em>(<var>s1</var>, <var>s2</var>, …)</em></dt>
<dd><p>Return a string containing all the arguments concatenated horizontally
with trailing white space preserved.
</p>
<p>For example:
</p>
<div class="example">
<pre class="example">cstrcat ("ab ", "cd")
⇒ "ab cd"
</pre></div>
<div class="example">
<pre class="example">s = [ "ab"; "cde" ];
cstrcat (s, s, s)
⇒ "ab ab ab "
"cdecdecde"
</pre></div>
<p><strong>See also:</strong> <a href="#XREFstrcat">strcat</a>, <a href="#XREFchar">char</a>, <a href="#XREFstrvcat">strvcat</a>.
</p></dd></dl>
<hr>
<div class="header">
<p>
Next: <a href="Converting-Numerical-Data-to-Strings.html#Converting-Numerical-Data-to-Strings" accesskey="n" rel="next">Converting Numerical Data to Strings</a>, Up: <a href="Creating-Strings.html#Creating-Strings" accesskey="u" rel="up">Creating Strings</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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