(base) MAC:Thu Oct 15:13:26:4240> jshell
|  Welcome to JShell -- Version 14.0.1
|  For an introduction type: /help intro

jshell> /open Foo.java

jshell> Foo f = new Foo();
f ==> Foo@31cefde0

jshell> foo.hashCode()
|  Error:
|  cannot find symbol
|    symbol:   variable foo
|  foo.hashCode()
|  ^-^

jshell> f.hashCode()
$3 ==> 835648992

jshell> Integer.toString(f, 16)
|  Error:
|  incompatible types: Foo cannot be converted to int
|  Integer.toString(f, 16)
|                   ^

jshell> Integer.toString(f.hashCode(), 16)
$4 ==> "31cefde0"

jshell> "a".hashCode()
$5 ==> 97

jshell> "b".hashCode()
$6 ==> 98

jshell> "c".hashCode()
$7 ==> 99

jshell> "aa".hashCode()
$8 ==> 3104

jshell> "ab".hashCode()
$9 ==> 3105

jshell> String s = "abcdefghijklnmopABCDEFGHIJKLMNOP"
s ==> "abcdefghijklnmopABCDEFGHIJKLMNOP"

jshell> "some" + "thing"
$11 ==> "something"

jshell> "some"*50
|  Error:
|  bad operand types for binary operator '*'
|    first type:  java.lang.String
|    second type: int
|  "some"*50
|  ^-------^

jshell> "some".repeat(50)
$12 ==> "somesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesomesome"

jshell> "some".repeat(-4)
|  Exception java.lang.IllegalArgumentException: count is negative: -4
|        at String.repeat (String.java:3586)
|        at (#13:1)

jshell> s[0]
|  Error:
|  array required, but java.lang.String found
|  s[0]
|  ^--^

jshell> s.charAt(0)
$14 ==> 'a'

jshell> (int) s.charAt(0)
$15 ==> 97

jshell> "a".compareTo("c")
$16 ==> -2

jshell> "a".compareTo("c") < 0
$17 ==> true

jshell> "a".compareTo("A") < 0
$18 ==> false

jshell> "abby".compareTo("acid") 
$19 ==> -1

jshell> "abby".compareTo("acid") < 0
$20 ==> true

jshell> "a".compareToIgnoreCase("A") 
$21 ==> 0

jshell> "a".compareToIgnoreCase("A") > 0
$22 ==> false

jshell> // "a" > "A"

jshell> "some".concat("thing")
$23 ==> "something"

jshell> s.contains("cdef")
$24 ==> true

jshell> s
s ==> "abcdefghijklnmopABCDEFGHIJKLMNOP"

jshell> // "cdef" in s

jshell> file = "quack.html"
|  Error:
|  cannot find symbol
|    symbol:   variable file
|  file = "quack.html"
|  ^--^

jshell> String file = "quack.html"
file ==> "quack.html"

jshell> file.endWith(".html")
|  Error:
|  cannot find symbol
|    symbol:   method endWith(java.lang.String)
|  file.endWith(".html")
|  ^----------^

jshell> file.endsWith(".html")
$27 ==> true

jshell> file.startWith("quack")
|  Error:
|  cannot find symbol
|    symbol:   method startWith(java.lang.String)
|  file.startWith("quack")
|  ^------------^

jshell> file.startsWith("quack")
$28 ==> true

jshell> String a = "aardvark"
a ==> "aardvark"

jshell> String b = "aardvark"
b ==> "aardvark"

jshell> a.equals(b)
$31 ==> true

jshell> a == b
$32 ==> true

jshell> c = new String("aardvark")
|  Error:
|  cannot find symbol
|    symbol:   variable c
|  c = new String("aardvark")
|  ^

jshell> String c = new String("aardvark")
c ==> "aardvark"

jshell> c == b
$34 ==> false

jshell> "ABC".equalsIgnoreCase("abc")
$35 ==> true

jshell> String.format("%s is eating %s in %s", "Chloe", "pizza", "PFM")
$36 ==> "Chloe is eating pizza in PFM"

jshell> String.format(".6f", 22.0/7)
$37 ==> ".6f"

jshell> String.format("%.6f", 22.0/7)
$38 ==> "3.142857"

jshell> String.format(5.2, 54.0/14);
|  Error:
|  no suitable method found for format(double,double)
|      method java.lang.String.format(java.lang.String,java.lang.Object...) is not applicable
|        (argument mismatch; double cannot be converted to java.lang.String)
|      method java.lang.String.format(java.util.Locale,java.lang.String,java.lang.Object...) is not applicable
|        (argument mismatch; double cannot be converted to java.util.Locale)
|  String.format(5.2, 54.0/14);
|  ^-----------^

jshell> String.format("%5.2f", 54.0/14);
$39 ==> " 3.86"

jshell> String.format("%5.2f%%", 54.0/14);
$40 ==> " 3.86%"

jshell> s
s ==> "abcdefghijklnmopABCDEFGHIJKLMNOP"

jshell> s.indexOf('l')
$42 ==> 11

jshell> s.indexOf('l', 13)
$43 ==> -1

jshell> s.indexOf("klmn")
$44 ==> -1

jshell> s.indexOf("bcd")
$45 ==> 1

jshell> s.indexOf("bcd", 5)
$46 ==> -1

jshell> // indexOf in Py is find

jshell> s.lastIndexOf("bcd")
$47 ==> 1

jshell> //lastIndexOf is Py's rfind

jshell> s = "    \t\t\n\n    "
s ==> "    \t\t\n\n    "

jshell> s.isBlank()
$49 ==> true

jshell> s.strip().length() == 0 
$50 ==> true

jshell> s.isEmpty()
$51 ==> false

jshell> s
s ==> "    \t\t\n\n    "

jshell> print(s)
|  Error:
|  cannot find symbol
|    symbol:   method print(java.lang.String)
|  print(s)
|  ^---^

jshell> System.out.println(s)
            

    

jshell> s.length()
$54 ==> 12

jshell> String q = "this and that"
q ==> "this and that"

jshell> q.replace('n', 'N')
$56 ==> "this aNd that"

jshell> q.replace("h", "HELLO")
$57 ==> "tHELLOis and tHELLOat"

jshell> q
q ==> "this and that"

jshell> String paddy = "        space           "
paddy ==> "        space           "

jshell> paddy.strip()
$60 ==> "space"

jshell> paddy.stripLeading()
$61 ==> "space           "

jshell> paddy.stripTrailing()
$62 ==> "        space"

jshell> //  strip, lstrip, rstrip

jshell> q
q ==> "this and that"

jshell> q[5:]
|  Error:
|  ']' expected
|  q[5:]
|     ^

jshell> q.substring(5)
$64 ==> "and that"

jshell> q.substring(0,5)
$65 ==> "this "

jshell> q.substring(3,5)
$66 ==> "s "

jshell> String.valueOf(true)
$67 ==> "true"

jshell> String.valueOf(5)
$68 ==> "5"

jshell> String.valueOf(23532)
$69 ==> "23532"

jshell> String.valueOf(6.02e23)
$70 ==> "6.02E23"

jshell> byte b = 42;
b ==> 42

jshell> String.valueOf(b)
$72 ==> "42"

jshell> Object o = new Object();
o ==> java.lang.Object@470e2030

jshell> String.value(o)
|  Error:
|  method value in class java.lang.String cannot be applied to given types;
|    required: no arguments
|    found:    java.lang.Object
|    reason: actual and formal argument lists differ in length
|  String.value(o)
|  ^----------^

jshell> String.valueOf(o)
$74 ==> "java.lang.Object@470e2030"

jshell> ArrayList<String> al = new ArrayList<>();
al ==> []

jshell> al.add("aardvark");
$76 ==> true

jshell> al.add("bat");
$77 ==> true

jshell> al.add("cougar");
$78 ==> true

jshell> al.add("dog
|  Error:
|  unclosed string literal
|  al.add("dog
|         ^

jshell> al.add("dog");
$79 ==> true

jshell> al
al ==> [aardvark, bat, cougar, dog]

jshell> al[0]
|  Error:
|  array required, but java.util.ArrayList<java.lang.String> found
|  al[0]
|  ^---^

jshell> al.get(0)
$81 ==> "aardvark"

jshell> al.get(3)
$82 ==> "dog"

jshell> al.get(4)
|  Exception java.lang.IndexOutOfBoundsException: Index 4 out of bounds for length 4
|        at Preconditions.outOfBounds (Preconditions.java:64)
|        at Preconditions.outOfBoundsCheckIndex (Preconditions.java:70)
|        at Preconditions.checkIndex (Preconditions.java:248)
|        at Objects.checkIndex (Objects.java:373)
|        at ArrayList.get (ArrayList.java:426)
|        at (#83:1)

jshell> al.size()
$84 ==> 4

jshell> al
al ==> [aardvark, bat, cougar, dog]

jshell> al.add(1, "aardwolf");

jshell> al
al ==> [aardvark, aardwolf, bat, cougar, dog]

jshell> al.append("elephant");
|  Error:
|  cannot find symbol
|    symbol:   method append(java.lang.String)
|  al.append("elephant");
|  ^-------^

jshell> al.add("elephant");
$88 ==> true

jshell> al
al ==> [aardvark, aardwolf, bat, cougar, dog, elephant]

jshell> al
al ==> [aardvark, aardwolf, bat, cougar, dog, elephant]

jshell>