[DOC] Enhanced RDoc for String (#5726)

Treats:

    #ljust
    #rjust
    #center
    #partition
    #rpartition

6 files changed, 98 insertions, 0 deletions

diff --git a/doc/string/center.rdoc b/doc/string/center.rdoc
new file mode 100644
index 0000000000..d53d921ad5
--- /dev/null
+++ b/doc/string/center.rdoc
@@ -0,0 +1,16 @@
+Returns a centered copy of +self+.
+
+If integer argument +size+ is greater than the size (in characters) of +self+,
+returns a new string of length +size+ that is a copy of +self+,
+centered and padded on both ends with +pad_string+:
+
+  'hello'.center(10)       # => "  hello   "
+  '  hello'.center(10)     # => "   hello  "
+  'hello'.center(10, 'ab') # => "abhelloaba"
+  'тест'.center(10)        # => "   тест   "
+  'こんにちは'.center(10)    # => "  こんにちは   "
+
+If +size+ is not greater than the size of +self+, returns a copy of +self+:
+
+  'hello'.center(5)  # => "hello"
+  'hello'.center(1)  # => "hello"
diff --git a/doc/string/ljust.rdoc b/doc/string/ljust.rdoc
new file mode 100644
index 0000000000..8e23c1fc8f
--- /dev/null
+++ b/doc/string/ljust.rdoc
@@ -0,0 +1,16 @@
+Returns a left-justified copy of +self+.
+
+If integer argument +size+ is greater than the size (in characters) of +self+,
+returns a new string of length +size+ that is a copy of +self+,
+left justified and padded on the right with +pad_string+:
+
+  'hello'.ljust(10)       # => "hello     "
+  '  hello'.ljust(10)     # => "  hello   "
+  'hello'.ljust(10, 'ab') # => "helloababa"
+  'тест'.ljust(10)        # => "тест      "
+  'こんにちは'.ljust(10)    # => "こんにちは     "
+
+If +size+ is not greater than the size of +self+, returns a copy of +self+:
+
+  'hello'.ljust(5)  # => "hello"
+  'hello'.ljust(1)  # => "hello"
diff --git a/doc/string/partition.rdoc b/doc/string/partition.rdoc
new file mode 100644
index 0000000000..ebe575e8eb
--- /dev/null
+++ b/doc/string/partition.rdoc
@@ -0,0 +1,24 @@
+Returns a 3-element array of substrings of +self+.
+
+Matches a pattern against +self+, scanning from the beginning.
+The pattern is:
+
+- +string_or_regexp+ itself, if it is a Regexp.
+- <tt>Regexp.quote(string_or_regexp)</tt>, if +string_or_regexp+ is a string.
+
+If the pattern is matched, returns pre-match, first-match, post-match:
+
+  'hello'.partition('l')      # => ["he", "l", "lo"]
+  'hello'.partition('ll')     # => ["he", "ll", "o"]
+  'hello'.partition('h')      # => ["", "h", "ello"]
+  'hello'.partition('o')      # => ["hell", "o", ""]
+  'hello'.partition(/l+/)     #=> ["he", "ll", "o"]
+  'hello'.partition('')       # => ["", "", "hello"]
+  'тест'.partition('т')       # => ["", "т", "ест"]
+  'こんにちは'.partition('に')  # => ["こん", "に", "ちは"]
+
+If the pattern is not matched, returns a copy of +self+ and two empty strings:
+
+  'hello'.partition('x') # => ["hello", "", ""]
+
+Related: String#rpartition, String#split.
diff --git a/doc/string/rjust.rdoc b/doc/string/rjust.rdoc
new file mode 100644
index 0000000000..24e7bf3159
--- /dev/null
+++ b/doc/string/rjust.rdoc
@@ -0,0 +1,16 @@
+Returns a right-justified copy of +self+.
+
+If integer argument +size+ is greater than the size (in characters) of +self+,
+returns a new string of length +size+ that is a copy of +self+,
+right justified and padded on the left with +pad_string+:
+
+  'hello'.rjust(10)       # => "     hello"
+  'hello  '.rjust(10)     # => "   hello  "
+  'hello'.rjust(10, 'ab') # => "ababahello"
+  'тест'.rjust(10)        # => "      тест"
+  'こんにちは'.rjust(10)    # => "     こんにちは"
+
+If +size+ is not greater than the size of +self+, returns a copy of +self+:
+
+  'hello'.rjust(5, 'ab')  # => "hello"
+  'hello'.rjust(1, 'ab')  # => "hello"
diff --git a/doc/string/rpartition.rdoc b/doc/string/rpartition.rdoc
new file mode 100644
index 0000000000..d24106fb9f
--- /dev/null
+++ b/doc/string/rpartition.rdoc
@@ -0,0 +1,24 @@
+Returns a 3-element array of substrings of +self+.
+
+Matches a pattern against +self+, scanning backwards from the end.
+The pattern is:
+
+- +string_or_regexp+ itself, if it is a Regexp.
+- <tt>Regexp.quote(string_or_regexp)</tt>, if +string_or_regexp+ is a string.
+
+If the pattern is matched, returns pre-match, last-match, post-match:
+
+  'hello'.rpartition('l')      # => ["hel", "l", "o"]
+  'hello'.rpartition('ll')     # => ["he", "ll", "o"]
+  'hello'.rpartition('h')      # => ["", "h", "ello"]
+  'hello'.rpartition('o')      # => ["hell", "o", ""]
+  'hello'.rpartition(/l+/)     # => ["hel", "l", "o"]
+  'hello'.rpartition('')       # => ["hello", "", ""]
+  'тест'.rpartition('т')       # => ["тес", "т", ""]
+  'こんにちは'.rpartition('に')  # => ["こん", "に", "ちは"]
+
+If the pattern is not matched, returns two empty strings and a copy of +self+:
+
+  'hello'.rpartition('x') # => ["", "", "hello"]
+
+Related: String#partition, String#split.
diff --git a/doc/string/split.rdoc b/doc/string/split.rdoc
index d93b76d9b4..2b5e14ddb6 100644
--- a/doc/string/split.rdoc
+++ b/doc/string/split.rdoc
@@ -82,3 +82,5 @@ Output:
   "abc"
   "def"
   "ghi"
+
+Related: String#partition, String#rpartition.