diff --git a/libraries/stdlib/src/kotlin/text/Strings.kt b/libraries/stdlib/src/kotlin/text/Strings.kt
index 57c44f98542..6256563df74 100644
--- a/libraries/stdlib/src/kotlin/text/Strings.kt
+++ b/libraries/stdlib/src/kotlin/text/Strings.kt
@@ -95,3 +95,155 @@ public fun Array<String>.join(separator: String = ", ", prefix: String = "", pos
 public fun Stream<String>.join(separator: String = ", ", prefix: String = "", postfix: String = "", limit: Int = -1, truncated: String = "..."): String {
     return joinToString(separator, prefix, postfix, limit, truncated)
 }
+/**
+ * Returns a substring before first occurrence of delimiter. In case of no delimiter, returns the whole string.
+ */
+public fun String.substringBefore(delimiter: Char): String {
+    val index = indexOf(delimiter)
+    return if (index == -1) this else substring(0, index)
+}
+
+/**
+ * Returns a substring before first occurrence of delimiter. In case of no delimiter, returns the whole string.
+ */
+public fun String.substringBefore(delimiter: String): String {
+    val index = indexOf(delimiter)
+    return if (index == -1) this else substring(0, index)
+}
+/**
+ * Returns a substring after first occurrence of delimiter. In case of no delimiter, returns an empty string.
+ */
+public fun String.substringAfter(delimiter: Char): String {
+    val index = indexOf(delimiter)
+    return if (index == -1) "" else substring(index + 1, length)
+}
+
+/**
+ * Returns a substring after first occurrence of delimiter. In case of no delimiter, returns an empty string.
+ */
+public fun String.substringAfter(delimiter: String): String {
+    val index = indexOf(delimiter)
+    return if (index == -1) "" else substring(index + delimiter.length, length)
+}
+
+/**
+ * Returns a substring before last occurrence of delimiter. In case of no delimiter, returns the whole string.
+ */
+public fun String.substringBeforeLast(delimiter: Char): String {
+    val index = lastIndexOf(delimiter)
+    return if (index == -1) this else substring(0, index)
+}
+
+/**
+ * Returns a substring before last occurrence of delimiter. In case of no delimiter, returns the whole string.
+ */
+public fun String.substringBeforeLast(delimiter: String): String {
+    val index = lastIndexOf(delimiter)
+    return if (index == -1) this else substring(0, index)
+}
+
+/**
+ * Returns a substring after last occurrence of delimiter. In case of no delimiter, returns an empty string.
+ */
+public fun String.substringAfterLast(delimiter: Char): String {
+    val index = lastIndexOf(delimiter)
+    return if (index == -1) "" else substring(index + 1, length)
+}
+
+/**
+ * Returns a substring after last occurrence of delimiter. In case of no delimiter, returns an empty string.
+ */
+public fun String.substringAfterLast(delimiter: String): String {
+    val index = lastIndexOf(delimiter)
+    return if (index == -1) "" else substring(index + delimiter.length, length)
+}
+
+/**
+ * Replace part of string at given range with replacement string
+ */
+public fun String.replaceRange(firstIndex: Int, lastIndex: Int, replacement: String): String {
+    if (lastIndex < firstIndex)
+        throw IndexOutOfBoundsException("Last index ($lastIndex) is less than first index ($firstIndex)")
+    val sb = StringBuilder()
+    sb.append(this, 0, firstIndex)
+    sb.append(replacement)
+    sb.append(this, lastIndex, length)
+    return sb.toString()
+}
+
+/**
+ * Replace part of string at given range with replacement string
+ */
+public fun String.replaceRange(range: IntRange, replacement: String): String {
+    if (range.end < range.start)
+        throw IndexOutOfBoundsException("Last index (${range.start}) is less than first index (${range.end})")
+    val sb = StringBuilder()
+    sb.append(this, 0, range.start)
+    sb.append(replacement)
+    sb.append(this, range.end, length)
+    return sb.toString()
+}
+
+/**
+ * Replace part of string before first occurrence of given delimiter with replacement string
+ */
+public fun String.replaceBefore(delimiter: Char, replacement: String): String {
+    val index = indexOf(delimiter)
+    return if (index == -1) replacement else replaceRange(0, index, replacement)
+}
+
+/**
+ * Replace part of string before first occurrence of given delimiter with replacement string
+ */
+public fun String.replaceBefore(delimiter: String, replacement: String): String {
+    val index = indexOf(delimiter)
+    return if (index == -1) replacement else replaceRange(0, index, replacement)
+}
+
+/**
+ * Replace part of string after first occurrence of given delimiter with replacement string
+ */
+public fun String.replaceAfter(delimiter: Char, replacement: String): String {
+    val index = indexOf(delimiter)
+    return if (index == -1) this else replaceRange(index + 1, length, replacement)
+}
+
+/**
+ * Replace part of string after first occurrence of given delimiter with replacement string
+ */
+public fun String.replaceAfter(delimiter: String, replacement: String): String {
+    val index = indexOf(delimiter)
+    return if (index == -1) this else replaceRange(index + delimiter.length, length, replacement)
+}
+
+/**
+ * Replace part of string after last occurrence of given delimiter with replacement string
+ */
+public fun String.replaceAfterLast(delimiter: String, replacement: String): String {
+    val index = lastIndexOf(delimiter)
+    return if (index == -1) this else replaceRange(index + delimiter.length, length, replacement)
+}
+
+/**
+ * Replace part of string after last occurrence of given delimiter with replacement string
+ */
+public fun String.replaceAfterLast(delimiter: Char, replacement: String): String {
+    val index = lastIndexOf(delimiter)
+    return if (index == -1) this else replaceRange(index + 1, length, replacement)
+}
+
+/**
+ * Replace part of string before last occurrence of given delimiter with replacement string
+ */
+public fun String.replaceBeforeLast(delimiter: Char, replacement: String): String {
+    val index = lastIndexOf(delimiter)
+    return if (index == -1) replacement else replaceRange(0, index, replacement)
+}
+
+/**
+ * Replace part of string before last occurrence of given delimiter with replacement string
+ */
+public fun String.replaceBeforeLast(delimiter: String, replacement: String): String {
+    val index = lastIndexOf(delimiter)
+    return if (index == -1) replacement else replaceRange(0, index, replacement)
+}
diff --git a/libraries/stdlib/test/text/StringTest.kt b/libraries/stdlib/test/text/StringTest.kt
index a1d584ec0fc..d8d9a9942cb 100644
--- a/libraries/stdlib/test/text/StringTest.kt
+++ b/libraries/stdlib/test/text/StringTest.kt
@@ -66,6 +66,62 @@ class StringTest {
     test fun indices() {
         assertEquals(0..4, "abcde".indices)
         assertEquals(0..0, "a".indices)
-        assertEquals(IntRange.EMPTY, "".indices)
+        assertTrue("".indices.isEmpty())
     }
+
+    test fun replaceRange() {
+        val s = "sample text"
+        assertEquals("sa??e text", s.replaceRange(2, 5, "??"))
+        assertEquals("sa??e text", s.replaceRange(2..5, "??"))
+        fails {
+            s.replaceRange(5..2, "??")
+        }
+        fails {
+            s.replaceRange(5, 2, "??")
+        }
+    }
+
+    test fun substringDelimited() {
+        val s = "-1,22,3+"
+        // chars
+        assertEquals("22,3+", s.substringAfter(','))
+        assertEquals("3+", s.substringAfterLast(','))
+        assertEquals("-1", s.substringBefore(','))
+        assertEquals("-1,22", s.substringBeforeLast(','))
+
+        // strings
+        assertEquals("22,3+", s.substringAfter(","))
+        assertEquals("3+", s.substringAfterLast(","))
+        assertEquals("-1", s.substringBefore(","))
+        assertEquals("-1,22", s.substringBeforeLast(","))
+
+        // non-existing delimiter
+        assertEquals("", s.substringAfter("+"))
+        assertEquals("", s.substringBefore("-"))
+        assertEquals(s, s.substringBefore("="))
+        assertEquals("", s.substringAfter("="))
+
+    }
+
+    test fun replaceDelimited() {
+        val s = "/user/folder/file.extension"
+        // chars
+        assertEquals("/user/folder/file.doc", s.replaceAfter('.', "doc"))
+        assertEquals("/user/folder/another.doc", s.replaceAfterLast('/', "another.doc"))
+        assertEquals("new name.extension", s.replaceBefore('.', "new name"))
+        assertEquals("/new/path/file.extension", s.replaceBeforeLast('/', "/new/path"))
+
+        // strings
+        assertEquals("/user/folder/file.doc", s.replaceAfter(".", "doc"))
+        assertEquals("/user/folder/another.doc", s.replaceAfterLast("/", "another.doc"))
+        assertEquals("new name.extension", s.replaceBefore(".", "new name"))
+        assertEquals("/new/path/file.extension", s.replaceBeforeLast("/", "/new/path"))
+
+        // non-existing delimiter
+        assertEquals("/user/folder/file.extension", s.replaceAfter("=", "doc"))
+        assertEquals("/user/folder/file.extension", s.replaceAfterLast("=", "another.doc"))
+        assertEquals("new name", s.replaceBefore("=", "new name"))
+        assertEquals("/new/path", s.replaceBeforeLast("=", "/new/path"))
+    }
+
 }