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DashaScript programming languagePredefined Function

Predefined functions for array

pop

Removes the last element from an array and returns it. If the array is empty, null is returned and the array is not modified.

Parameters

None

Returns

number - the removed element from the array if the array was not empty, null otherwise.

Examples

node some_node {
    do {
        var arr: number[] = [1,2];
        var el1 = arr.pop();
        #log(el1); // 2
        #log(arr.pop()); // 1
        #log(arr.pop()); // null
    }
}

shift

Removes the first element from an array and returns that element. If the array is empty, null is returned and the array is not modified.

Parameters

None

Returns

number - first element of the array if the array is not empty, null otherwise.

Examples

node some_node {
    do {
        var arr: number[] = [1,2];
        var el1 = arr.shift();
        #log(el1); // 1
        #log(arr.shift()); // 2
        #log(arr.shift()); // null
    }
}

push

Appends new element to the end of an array.

Note:

  • New element must be of a type compatible to a type of an array. For example, you can add an element of type string or "some_string_literal" to an array of type string[]. But you can not add an element of type number to an array of type string[].

Parameters

NameTypeDescription
valueType compatible with a type of the arraythe value of the element to add

Returns

empty

Examples

node some_node {
    do {
        var arr: number[] = [1,2];
        arr.push(3);
        #log(arr); // [1,2,3]
        arr.push("s"); // compile error
    }
}

unshift

Prepends new element to the beginning of an array.

Note:

  • New element must be of a type compatible to a type of an array. For example, you can add an element of a type string or "some_string_literal" to an array of a type string[]. But you can not add an element of type number to an array of a type string[].

Parameters

NameTypeDescription
valueType compatible with a type of an arraythe value of the element to add

Returns

empty

Examples

node some_node {
    do {
        var arr: number[] = [1,2];
        arr.unshift(3);
        #log(arr); // [3,1,2]
        arr.unshift("s"); // compile error
    }
}

append

Appends new elements to the end of an array.

Note:

  • The element to be added must be of a type compatible to a type of an array. For example, you can add elements of type string[] or "some_string_literal"[] to an array of type string[]. But you can not add elements of type number[] to an array of type string[].

Parameters

NameTypeDescription
valuesType compatible with type of arraythe values of the elements to append

Returns

empty

Examples

node some_node {
    do {
        var arr: number[] = [1,2];
        arr.append([3,4,5]);
        #log(arr); // [1,2,3,4,5]
        arr.append(["s"]); // compile error
    }
}

prepend

Prepends new elements to the beginning of an array.

Note:

  • The element to be added must be of a type compatible to a type of an array. For example, you can add elements of type string[] or "some_string_literal"[] to an array of type string[]. But you can not add elements of type number[] to an array of type string[].

    Parameters

    NameTypeDescription
    valuesType compatible with type of arraythe values of the elements to append

Returns

empty

Examples

node some_node {
    do {
        var arr: number[] = [1,2];
        arr.prepend([3,4,5]);
        #log(arr); // [3,4,5,1,2]
        arr.prepend(["s"]); // compile error
    }
}

length

Returns the length of an array.

Parameters

None

Returns

number - length of an array.

Examples

node some_node {
    do {
        var arr: number[] = [];
        #log(arr.length()); // 0
        arr.append([1,2]);
        arr.prepend([3,4,5]);
        #log(arr.length()); // 5
        arr.pop();
        #log(arr.length()); // 4
        arr.shift();
        #log(arr.length()); // 3
    }
}

reverse

Returns a new array with the elements of the source in reversed order. The elements of reversed array are the same references as elements of the source array.

The source array stays unmodified.

Parameters

None

Returns

A new array of the same type with elements of the source in reversed order.

Examples

node some_node {
    do {
        var arr: number[] = [1,2,3];
        var revArr = arr.reverse();
        #log(revArr); // [3,2,1]
        #log(arr); // [1,2,3]
    }
}

remove

Removes elements in range [start, start+deleteCount) from an array and returns deleted elemenets.

A negative value of start index means an offset from the end of the array, i.e. arr.remove(-2) is equivalent for arr.remove(arr.length() - 2).

If deleteCount is omitted, or if deleteCount >= array.length() - start, then all the elements from start to the end of the array will be deleted.

Note:

  • the float value of the start index will be truncated to integer value.

Parameters

NameTypeDescription
startnumberinteger index of the first removed element
deleteCountnumber?number of elements to remove (not including the element at index start + deleteCount)

Returns

An array containing the removed elements.

Examples

node some_node {
    do {
        var arr: number[] = [1,2,3,4,5,6];
        #log(arr.remove(3,2)); // [4,5]
        #log(arr); // [1,2,3,6]

        set arr = [1,2,3,4,5,6];
        #log(arr.remove(3,100)); // [4,5,6]
        #log(arr); // [1,2,3]

        set arr = [1,2,3,4,5,6];
        #log(arr.remove(3)); // [4,5,6]
        #log(arr); // [1,2,3]

        set arr = [1,2,3,4,5,6];
        #log(arr.remove(100)); // []
        #log(arr); // [1,2,3,4,5,6]

        set arr = [1,2,3,4,5,6];
        #log(arr.remove(2, 0)); // []
        #log(arr); // [1,2,3,4,5,6]

        set arr = [1,2,3,4,5,6];
        // remove 2 last elements
        #log(arr.remove(-2)); // [5,6]
        #log(arr); // [1,2,3,4]

        set arr = [1,2,3,4,5,6];
        // 1.7 is truncated  to 1
        #log(arr.remove(1.7)); // [2,3,4,5,6]
        #log(arr); // [1]
    }
}

slice

Returns a copy of a section extracted from an array. Input parameters start and end define the section of the array as the range [start,end).

A negative value of an index (start or end) means an offset from the end of the array (please, see the examples).

If start is omitted than slice will extract elements starting from the index 0.

If end is omitted or end >= array.length() than slice will extract elements through to the end of array.

Note:

  • the float value of an index will be truncated to integer value.

Parameters

NameTypeDescription
startnumber?integer index at which to start the extraction
endnumber?integer index at which to end the extraction (not including)

Returns

A new array containing the extracted elements.

Examples

node some_node {
    do {
        var arr: number[] = [1,2,3,4,5,6];
        #log(arr.slice()); // [1,2,3,4,5,6]
        #log(arr.slice(2,4)); // [3,4]
        #log(arr.slice(2)); // [3,4,5,6]
        #log(arr.slice(-2)); // [5,6]
        // 2.9 is truncated to 2
        #log(arr.slice(2.9)); // [3,4,5,6]
        #log(arr.slice(2,10)); // [3,4,5,6]
    }
}

join

Converts all the elements of an array into a string, separated by the specified separator string.

If separator omitted, the array elements are separated with a comma (","). If separator is an empty string, all elements are joined without any characters in between them.

Parameters

NameTypeDescription
separatorstring?string to separate each pair of adjacent elements of the array

Returns

string - a string with all array elements joined.

Examples

node some_node {
    do {
        var numArr: number[] = [1,2,3,4,5,6];
        #log(numArr.join()); // "1,2,3,4,5,6"
        #log(numArr.join("-")); // "1-2-3-4-5-6"
        #log(numArr.join("")); // "123456"

        var strArr: string[] = ["h","e","l","l","o"];
        #log(strArr.join("")); // "hello"

        var boolArr: boolean[] = [true,false];
        #log(boolArr.join()); // "true,false"

        // objects should be stringified manually
        var objArr: unknown[] = [{a: 1}, {b:2}];
        #log(objArr.join()); // "[object Object],[object Object]"
    }
}
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