diff --git a/php/src/str.php b/php/src/str.php
index b0f3497..347726b 100644
--- a/php/src/str.php
+++ b/php/src/str.php
@@ -268,6 +268,21 @@ class str {
     $s .= $prefix.$text.$suffix;
   }
 
+  /**
+   * dans $s, faire les remplacements $key => $value du tableau $replaces
+   *
+   * si $verifix_order, le tableau est réordonné par taille de chaine source
+   */
+  static final function replace(?string $s, ?array $replaces, bool $verifix_order=true): ?string {
+    if ($s === null || $replaces === null) return $s;
+    if ($verifix_order) {
+      uksort($replaces, function ($a, $b) {
+        return -cv::compare(strlen($a), strlen($b));
+      });
+    }
+    return str_replace(array_keys($replaces), array_values($replaces), $s);
+  }
+
   /** si $text est non vide, ajouter $prefix$text$suffix à $s en séparant la valeur avec un espace */
   static final function add(?string &$s, ?string $text, ?string $prefix=null, ?string $suffix=null): void {
     self::addsep($s, " ", $text, $prefix, $suffix);
diff --git a/php/tests/strTest.php b/php/tests/strTest.php
index 2d69303..c03997e 100644
--- a/php/tests/strTest.php
+++ b/php/tests/strTest.php
@@ -5,7 +5,22 @@ namespace nulib;
 use nulib\tests\TestCase;
 
 class strTest extends TestCase {
-  function testSplit_tokens() {
+  function test_replace() {
+    self::assertSame("premier deuxieme", str::replace("first second", [
+      "first" => "premier",
+      "second" => "deuxieme",
+    ]));
+    self::assertSame("avant OK", str::replace("prefix prefixsuffix", [
+      "prefix" => "avant",
+      "prefixsuffix" => "OK",
+    ]));
+    self::assertSame("avant avantsuffix", str::replace("prefix prefixsuffix", [
+      "prefix" => "avant",
+      "prefixsuffix" => "OK",
+    ], false));
+  }
+
+  function test_split_tokens() {
     self::assertNull(str::split_tokens(null));
     self::assertSame([], str::split_tokens(""));
     self::assertSame(["token"], str::split_tokens("token"));
@@ -13,7 +28,7 @@ class strTest extends TestCase {
     self::assertSame(["t", "u", "v", "w"], str::split_tokens("\nt\n\nu\r\nv\rw"));
   }
 
-  function testCamel2us() {
+  function test_camel2us() {
     self::assertSame("a", str::camel2us("a"));
     self::assertSame("aa", str::camel2us("aa"));
     self::assertSame("aaa", str::camel2us("aaa"));