Operators

JS4Scratch Reference Manual:

For a full description of all JavaScript operators please refer to W3schools JS

Add

Syntax:

num + num

Example:

spriteA.whenFlag(function () {
    this.show()
    score = 0
    this.sayWait('The score at the moment is:',2)
    this.sayWait(score,2)
    this.sayWait('but if we add 2 it becomes:',2)
    score = score + 2
    this.sayWait(score,2) 
})
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Subtract

Syntax:

num - num

Example:

spriteA.whenFlag(function () {
    this.show()
    score = 10
    this.sayWait('The score at the moment is:',2)
    this.sayWait(score,2)
    this.sayWait('but if we substract 2 it becomes:',2)
    score = score - 2
    this.sayWait(score,2) 
})
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Multiply

Syntax:

num * num

Example:

spriteA.whenFlag(function () {
    this.show()
    score = 10
    this.sayWait('The score at the moment is:',2)
    this.sayWait(score,2)
    this.sayWait('but if we multiply by 2 it becomes:',2)
    score = score * 2
    this.sayWait(score,2) 
})
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Divide

Syntax:

num / num

Example:

spriteA.whenFlag(function () {
    this.show()
    score = 10
    this.sayWait('The score at the moment is:',2)
    this.sayWait(score,2)
    this.sayWait('but if we divide by 2 it becomes:',2)
    score = score / 2
    this.sayWait(score,2) 
})
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Pick Random

Syntax:

Math.floor(Math.random() * (max - min)) + min

Example:

spriteA.whenFlag(function () {
    this.show()
    this.sayWait('I will display a random integer 1-10 every 1 second',2)
    score = 0
    while (true) {
        score = Math.floor(Math.random() * (10 - 1)) + 1
        this.sayWait(score,1)
    }
})
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Greater Than

Syntax:

num > num

Example:

spriteA.whenFlag(function () {
    this.show()
    score = 0
    this.sayWait('Increment the score and determine if greater than 10',2)
    while (true) {
        score = score + 1
        this.wait(0.5)
        if (score > 10) {
            this.say('score is now larger than 10')
        }
    } 
})
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Less Than

Syntax:

num < num

Example:

spriteA.whenFlag(function () {
    this.show()
    score = 10
    this.sayWait('Decrement the score and determine if less than 0',2)
    while (true) {
        score = score - 1
        this.wait(0.5)
        if (score < 0) {
            this.say('score is now less than 0')
        }
    } 
})
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Equal To

Syntax:

num === num

note: same type and value

Example:

spriteA.whenFlag(function () {
    this.show()
    score = 10
    this.sayWait('Decrement the score and determine if equal to 5',2)
    while (true) {
        score = score - 1
        this.wait(1)
        if (score === 5) {
            this.sayWait('score is now equal to 5',2)
        } else {
            this.say('Score is not equal to 5')
        }
    } 
})
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AND

Syntax:

var && var

Example:

spriteA.whenFlag(function () {
    this.show()
    this.sayWait('Press the Up and Down keys when you are ready',2)
    while (true) {
        if (stage.isKeyPressed('ArrowUp') && stage.isKeyPressed('ArrowDown')) {
            this.say('Both Up and Down arrow keys are pressed')
        } else {
            this.say('Both Up and Down arrow keys are NOT pressed')
        }
    } 
})
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OR

Syntax:

var || var

Example:

spriteA.whenFlag(function () {
    this.show()
    this.sayWait('Press either Up or Down keys when you are ready',2)
    while (true) {
        if (stage.isKeyPressed('ArrowUp') || stage.isKeyPressed('ArrowDown')) {
            this.say('either Up or Down arrow key is pressed')
        } else {
            this.say('neither Up nor Down arrow key is pressed')
        }
    } 
})
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NOT

Syntax:

!(condition)

Example:

spriteA.whenFlag(function () {
    this.show()
    score = 10
    this.sayWait('Decrement the score and determine if not equal to 5',2)
    while (true) {
        score = score - 1
        this.wait(1)
        if (!(score === 5)) {
            this.sayWait('score is not equal to 5',2)
        } else {
            this.sayWait('Score is equal to 5',2)
        }
    } 
})
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Round

Syntax:

Math.round (variableName)

Example:

spriteA.whenFlag(function () {
    this.show()
    score = 5.8
    this.sayWait('The score at the moment is:',2)
    this.sayWait(score,2)
    this.sayWait('but if we round that it becomes:',2)
    score = Math.round (score)
    this.sayWait(score,2) 
})
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