NinjaScript > Language Reference > Common > Alert, Debug, Share

Definition

Converts object data to a string format and appends the specified value as text to the NinjaScript Output window. Printing data to the NinjaScript Output window is a useful debugging technique to verify values while developing your custom NinjaScript object.

Notes: The Print() method only targets the Output tab recently specified by set PrintTo property.

Method Return Value

This method does not return a value.

Syntax

Print(object value)

Warning: High frequency of Print() method calls can represent a performance hit on your PC. Please see the NinjaScript section of the Performance Tips article for more information.

Parameters

value

The object to print to the output window

Tips:

1.You can format prices aligned for easier debugging by using the ToString() method. E.g., Low[0].ToString("0.00") forces the format from 12.5 to 12.50. Low[0].ToString("0.000") forces 12.500.

2.You can format one or more objects in a specified string with the text equivalent of a corresponding object's value for better maintainability using the .NET string.Format() method. Please see the examples below.

Examples

Passing objects directly to Print() method
protected override void OnBarUpdate() { // Generates a message Print("This is a message"); //Output: This is a message Print("The high of the current bar is : " + High[0]); //Output: The high of the current bar is : 2112.75 // Prints the current bar SMA value to the output window Print(SMA(Close, 20)[0]); //Output: 2110.5; }

Passing string.Format() directly to Print() method
protected override void OnBarUpdate() { //Format and Print each bar value to the output window Print(string.Format("{0};{1};{2};{3};{4};{5}", Time[0], Open[0], High[0], Low[0], Close[0], Volume[0])); //Output: 2/24/2015 11:01:00 AM;2110.5;2110.5;2109.75;2110;1702 }

Storing and reusing variables in Print() method

protected override void OnBarUpdate()
{
//store the Close[0] value in a variable which can be printed later*
double myValue = Close[0];

//create and store a custom error message
string myError = string.Format("Error on Bar {0}, value {1} was not expected", CurrentBar, myValue);

//*Storing the value adds better reusability of the error message above for other objects
//For example later down on line #19 we replace myValue = Close[0] with another double value Low[0]
//This allows you to reuse the custom error formatted above on line #7 without repeating yourself

//our first test case, if true print our error
if(myValue > High[0])
Print(myError);
//Output: Error on Bar 233, value 1588.25 was not expected

//reassign myValue
myValue = Low[0];

//our second test case (now uses Low[0]), if true print our error
if(myValue > Close[0])
Print(myError);
//Output: Error on Bar 57, value 1585.5 was not expected
}