Chapter 34. Zend_Measure

Table of Contents

34.1. Introduction
34.2. Creation of Measurements
34.2.1. Creating measurements from integers and floats
34.2.2. Creating measurements from strings
34.2.3. Measurements from localized strings
34.3. Outputting measurements
34.3.1. Automatic output
34.3.2. Outputting values
34.3.3. Output with unit of measurement
34.3.4. Output as localized string
34.4. Manipulating Measurements
34.4.1. Convert
34.4.2. Add and subtract
34.4.3. Compare
34.4.4. Compare
34.4.5. Manually change values
34.4.6. Manually change types
34.5. Types of measurements
34.5.1. Hints for Zend_Measure_Binary
34.5.2. Hints for Zend_Measure_Number
34.5.3. Roman numbers

34.1. Introduction

Zend_Measure_* classes provide a generic and easy way for working with measurements. Using Zend_Measure_* classes, you can convert measurements into different units of the same type. They can be added, subtracted and compared against each other. From a given input made in the user's native language, the unit of measurement can be automatically extracted. Numerous units of measurement are supported.

Example 34.1. Converting measurements

The following introductory example shows automatic conversion of units of measurement. To convert a measurement, its value and its type have to be known. The value can be an integer, a float, or even a string containing a number. Conversions are only possible for units of the same type (mass, area, temperature, velocity, etc.), not between types.

$locale = new Zend_Locale('en');
$unit = new Zend_Measure_Length(100, Zend_Measure_Length::METER, $locale);

// Convert meters to yards
echo $unit->convertTo(Zend_Measure_Length::YARD);

Zend_Measure_* includes support for many different units of measurement. The units of measurement all have a unified notation: Zend_Measure_<TYPE>::NAME_OF_UNIT, where <TYPE> corresponds to a well-known physical or numerical property. . Every unit of measurement consists of a conversion factor and a display unit. A detailed list can be found in the chapter Types of measurements .

Example 34.2. The meter measurement

The meter is used for measuring lengths, so its type constant can be found in the Length class. To refer to this unit of measurement, the notation Length::METER must be used. The display unit is m.

echo Zend_Measure_Length::STANDARD;  // outputs 'Length::METER'
echo Zend_Measure_Length::KILOMETER; // outputs 'Length::KILOMETER'

$unit = new Zend_Measure_Length(100,'METER');
echo $unit;
// outputs '100 m'