How to Use String and Container Types

1. String

String is a very useful data type. Almost every script people write involves some string manipulation. Luban offers a rich set of tools to do that easily. String type key word is string. The below example Luban code shows operations for string type.

1.1 Basic Set of Operators

Read/write with indexing:

s = “Hello”; c = s[1]; // c is ‘e’

s = “Hello”; s[0] = ‘h’; // s becomes “hello”

Data member iteration:

s = “Hello”;

foreach( c in s ) std::console().write( c ); // will print out Hello

Arithmetic like operators

s = “Hello”*2; // result is “HelloHello”

s = -“Hello”; // result is “olleH”

s = “Hello” + “World”; // result “HelloWorld”

1.2 Member functions

// The split() function that everyone wants

s = “Hello World”;

words = s.split( ); // words is a vector [“Hello”, “World”]

// trim white space from front and back

s = “ Hello”;

s.trimfront(); // s becomes “Hello”

s. = “Hello \n\t”;

s.trimback(); // s become “Hello”

//search

s=”Hello”;

index=s.find(“Hell”); // index = 0

index2=s.find(“Hell”,2); // index = null, faled to find Hell starting from index 2l

index3=s.find(“Heaven”); // index3 = null failed to find

truth=s.contains(“Hell”); // truth = true

sub=s.substr(2,3); // sub=”ll” from index 2 to index 3

// content manipulation

s=”Hello”;

s.replace(“Hell”, “Heaven”); // now s becomes “Heaveno”

s.lower(); // s becomes “heaveno”;

s.upper(); // s = “HEAVENO”

s.remove(6); // s=”HEAVEN”, with 0 at index 6 removed

s.remove(“A”); // s=”HEVEN”;

s.insert(1, “A”); // s=”HEAVEN”;

s.clear(); // s=””

2. Vector, Map and Set

Vector type key word is vector.

x = 1; y=2; z=3; v = [x,y,z,4]; // v = [ 1,2,3,4]

v[0] = 10; // v = [10,2,3,4]

total = 0; foreach( element in v ) total += element; // total =

v.sort(); // v become [2,3,4,10]

v2 = v+ [11,12,13]; // v2 become [2,3,4,10,11,12,13]

v2.remove(0); // v2 become [3,4,10,11,12,13]

v2.removeobj(10); // v2 become [3,4,11,12,13]

v3 = [ v2,v2]; // v3 is two dimensional vector

// push and pop

x=[1,2];

x.pushfirst(0); // x =[0,1,2]

x.pushlast(3); // x=[0,1,2,3]

y=x.popfirst(); // y=0, x=[1,2,3];

z=x.poplast(); // y=3, x=[1,2]

//sub vector

x=[0,1,2,3];

y=x.subvec(2,3); // y=[2,3]

.

Map type key word is map. Keys are unique in a map. Code examples:

x=1; y=2; z = 3; word2number = { “one” : x, “two” : y, “three” : z };

word2number[“four”] = 4; // insert or replace

word2nubmer.remove(“one”); // remove key “one” and associated 1

word2number.insert(“two”,2.0); // no impact because key already exist

union = word2number + { “five”:5, “six”:6};

foreach(key,val in word2number ) std::console().writeline(key,’ ‘,val); // iterate

emptymap = {:};

Set key word is set. Set is simply a collection of unique values. See examples:

oneset = { 1, “hello”, 3.14 };

another = { 1,2};

union = oneset + another; // union = { 1,2,”hello”,3.14}

minus = oneset – another ; // minus = { “hello”, 3.14}, common values removed

joint = oneset – minus; // joint = {1}, the common values of oneset and another

foreach( val in oneset ) std::console().writeline(val); // iterate

emptyset = {};

Casting operations among vector, set and map:

oneset = { 1,2,3}; onevec = vector(oneset);

keyvec=[‘a’,’b’]; valvec = [‘A’,’B’]; onemap = map(keyvec, valvec);