PHP floatscan intensively optimize your blocks of code and it is useful to know about their usage. This article will cover floats in detail including their types and syntax used in PHP. We will also take a look at their formatting and how strings can be converted to float numbers. A learning journey full of knowledge about floats awaits you in this article.
Contents
- PHP Float
- Syntax of Float in PHP
- – PHP_FLOAT_MAX
- – PHP_FLOAT_DIG
- Types of Floating Point Numbers
- How to Format a Float?
- – Do you Need the Number?
- What About the Decimal Point?
- How To Convert Strings To Float Numbers?
- – First Method of Conversion
- – Second Method: Typecasting
- – Third Method: Mathematical Operations
- Floatval() And Intval() Functions
- Conclusion
PHP Float
Float is an important data type that can be used to set fractional values with decimal points. It includes numbers that can be extended to their exponential form. These numbers are also called floating point numbers.
PHP has an interesting feature of automatically converting the data type of those values to float which are quite large and contain decimal points.
With a maximum precision of fourteen digits, float numbers tend to lose their precision if they are above this maximum range for digit values. Therefore, you can use thePHP float precisionto store values depending on the limit of associated platforms. You can check if variables in PHP are float by using the is_float() and is_double() functions.
Syntax of Float in PHP
We advise you to use float as a keyword just before the variable. This is important as it will set float as the data type as that variable is being initialized. In this way, the float value can be set to its initialized variable. You just have to mention it after the name of that variable and an equal sign.
You can change the float value on any instance in PHP except for one case. The float value cannot be changed if its variable has been declared static. There are certain predefined constants that must be kept in mind while using float as a data type.
– PHP_FLOAT_MAX
PHP_FLOAT_MAX is an important predefined constant that represents the largest floating point number presented in a PHP script. PHP_FLOAT_MIN represents the smallest float number that can be presented. Furthermore, – PHP_FLOAT_MAX is also a predefined constant that is used for the smallest negative floating number. You must ensure that you mention its subtraction sign as it is the only different factor in – PHP_FLOAT_MAX compared to PHP_FLOAT_MAX.
– PHP_FLOAT_DIG
Moreover, PHP_FLOAT_DIG can be used for numbers with decimal digits that are intended to be rounded into a float. It can also be used to round that float back to those decimal digits without the risk of loss in precision. ThePHP floating pointcan use PHP_FLOAT_EPSILON as a predefined constant for the smallest positive number represented with a variable.
You can use float as a data type in numerous applications. PHP enables you to use float numbers as marks, currency, and even percentages where decimal points are prevalent. Basic operations like multiplication, addition, division, and subtraction can also be performed on float numbers in PHP. The output values, stored for these operations, depending on the system.
Types of Floating Point Numbers
There are three types of floating point numbers in PHP:
- Short floating point numbers
- Long floating point numbers
- Double floating point numbers
The smallest fixed precision that can be provided through implementation in PHP is called a short floating point number. The minimum exponent size and precision, of this point number, will be five bits and thirteen bits respectively. While it will provide a precision of up to four decimal places.
One of the largest fixed precisions that can be provided through implementation is called the long floating point number. The minimum exponent size and precision will be eight bits and fifty bits respectively. The precision of this point number will be up to fourteen decimal places.
One of the fixed precisions that can be provided through implementation is called double floating point number. The minimum exponent size and precision will be the same as that of a long floating point number. It will also provide a precision of up to fourteen decimal places.
How to Format a Float?
A float can be formatted by the number_format() function with grouped thousands. However, it is important to note that this function will not support those program executions that have three parameters. The parameters assigned to the values, for this function, are comprised of number, decimals, decimal point, and separator.
– Do you Need the Number?
The number is a mandatory parameter, for values, which is comprised of those numbers that have to be formatted. PHP will format the numbers with a comma and without decimal points as the thousands separator if no other parameters have been set. ThePHP format floatalso includes a parameter named decimal which specifies the included decimals. It is an optional parameter that, if set, will format the numbers with dots as their decimal points.
What About the Decimal Point?
Moving on, a decimal point is also an optional parameter that specifies the strings that have to be used for decimal points.Whereas, a separator can be used to specify the strings that can be used for the thousands separator. It is up to you to use this parameter as it is optional because only the first character of the separator will be used. However, you must keep in mind that the use of all parameters will become mandatory if the separator is used.
The return values for the number_format() function will return all the numbers that have been formatted. The changelog for this function will support multiple bytes from the decimal point and separator parameters. Older versions of PHP only used the first byte of all separators.
How To Convert Strings To Float Numbers?
PHP enables you to effortlessly convert strings to float numbers based on your preferences. However, there will be not much need to do that as PHP allows implicit type conversions. Still, there are four prevalent methods with which you can convert strings to float numbers.
– First Method of Conversion
The first method involves the number_format() function that can also be used to convert strings into float numbers. The formatted numbers are returned if the blocks of code are executed successfully. In another case, a warning named E_WARNING is given upon failure of the execution.
– Second Method: Typecasting
PHP convert string to float can be doneby a second method called typecasting. With this method, strings can be directly converted to float numbers and doubles. It can also convert them to the primitive type of integers. We advise you to use typecasting in most cases as it is easier and does not require the usage of any function.
– Third Method: Mathematical Operations
You can also convert strings to float numbers by performing mathematical operations and adding zero with the values. In this way, the strings will be implicitly converted to their respective float numbers. ThePHP string to floatconversion also involves the usage of the floatval() function. This function is often used for the conversion of strings into their respective float numbers.
Floatval() And Intval() Functions
Floatval() is an inbuilt function in PHP that can be used to return the float values of variables for your blocks of code. In this way, the strings will be converted to their corresponding float numbers. It is important to compare the floatval() function with intval() as they have a similar purpose for usage. The intval() function is used to convert strings into their corresponding integer values.
It is an inbuilt function within PHP with which you can return the integer values of variables for your blocks of code. The function accepts an optional and a mandatory parameter to convert the associated strings to their respective integers. These parameters include a variable named $var which is the mandatory one.
This is because it serves in the script to be converted to the respective integer value. In addition, $base is the optional parameter with which the base to convert $var to its integer value is specified. The intval() function will return the corresponding integers of $var as the value. You also have to take the case into account in which the $base has not been specified.
Conclusion
Let’s have a quick revision of what has been covered so far. We learned about float as a data type to set fractional values with decimal points and extend numbers to their exponential form. We looked at the syntax that included float as a keyword to set it as the data type and initialize the variable. We saw that the syntax involves certain predefined constants as well. Here are the specifics:
There was also a mention of three types of floating-point numbers named short, long and double.- We learned how to format a float using the number_format() function with grouped thousands.
- Certain parameters named number, decimals, decimal point, and separator are assigned to the values for this function.
- We also looked at four methods to convert strings into float numbers.
- These methods involved the usage of the number_format() function, floatval() function, typecasting, performing basic mathematical operations, and adding zero with the numbers.
- Finally, we compared the floatval() and intval() functions and saw how they convert strings into float numbers and integers respectively.
There was also a mention of three types of floating-point numbers named short, long and double.If you are unsure about how to use float in PHP, this guide is all that you need. You can come back to it whenever you need to. Happy Coding!
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FAQs
How to set float precision in PHP? ›
You can use number_format() to achieve this: echo number_format((float) $number, $precision, '. ', ''); This would convert 1518845.756789 to 1518845.757 .
How to compare two float values in PHP? ›Comparing floats for equality has a naive O(n) algorithm. You must convert each float value to a string, then compare each digit starting from the left side of each float's string representation using integer comparison operators. PHP will autocast the digit in each index position to an integer before the comparison.
How to use float in PHP? ›In PHP, the Float data type is used to set fractional values. A float is a number with a decimal point and can be extended to exponential form. Float is also called a floating-point number. Various ways to represent float values are 3.14, 4.75, 5.88E+20, etc.
What is the maximum precision of float in PHP? ›PHP Floats
The float data type can commonly store a value up to 1.7976931348623E+308 (platform dependent), and have a maximum precision of 14 digits.
To format a number to 2 decimal places in PHP, you can use the round() function and pass the number and 2 as arguments to the round() function. round() function accepts a number and the number of decimal places to round to as arguments, and it returns the rounded number as a float.
How do you add precision to a float? ›To set the precision in a floating-point, simply provide the number of significant figures (say n) required to the setprecision() function as an argument. The function will format the original value to the same number of significant figures (n in this case).
What is a better way to compare floating point values? ›To compare two floating point values, we have to consider the precision in to the comparison. For example, if two numbers are 3.1428 and 3.1415, then they are same up to the precision 0.01, but after that, like 0.001 they are not same.
Why is float not precise? ›Floating-point decimal values generally do not have an exact binary representation. This is a side effect of how the CPU represents floating point data. For this reason, you may experience some loss of precision, and some floating-point operations may produce unexpected results.
Why is double better than float values? ›double is mostly used for calculations in programming to eliminate errors when decimal values are being rounded off. Although float can still be used, it should only be in cases when we're dealing with small decimal values. To be on the safe side, you should always use double .
What is float () used for? ›Float() is a method that returns a floating-point number for a provided number or string. Float() returns the value based on the argument or parameter value that is being passed to it. If no value or blank parameter is passed, it will return the values 0.0 as the floating-point output.
How to display float value in PHP? ›
PHP | floatval() Function
The floatval() function is an inbuilt function in PHP which returns the float value of a variable. Parameters: This function accepts one parameter which is mandatory and described below: $var: The variable whose corresponding float value will be returned.
A 32-bit float has about 7 digits of precision and a 64-bit double has about 16 digits of precision.
How precise can a float be? ›With a data type, there is a limited number of bits. Those bits cannot accurately represent a value that requires more than that number of bits. The data type float has 24 bits of precision. This is equivalent to only about 7 decimal places.
What is the precision of 32-bit floating-point? ›32-bit single precision, with an approximate range of 10 -101 to 10 90 and precision of 7 decimal digits. 64-bit double precision, with an approximate range of 10 -398 to 10 369 and precision of 16 decimal digits.
How do I restrict float to 2 decimal places? ›To limit a float to two decimal points in Python, you can use the round function. The round function takes a number and the number of decimal points to round to as arguments, and returns the rounded number. In this case, the float x is rounded to two decimal points, resulting in the value 3.14.
How do you write a float value up to 2 decimal places? ›format("%. 2f", 1.23456); This will format the floating point number 1.23456 up-to 2 decimal places, because we have used two after decimal point in formatting instruction %.
How do I truncate a float to two decimals? ›Using ceil() function
Create a variable to store the input floating-point number. Use the ceil() function(returns a ceiling value of the number i.e., the smallest integer greater than or equal to the number), to round the number upto the 2 decimal places and print the resultant number.
The data type float has 24 bits of precision. This is equivalent to only about 7 decimal places. (The rest of the 32 bits are used for the sign and size of the number.) The number of places of precision for float is the same no matter what the size of the number.
How do you reduce the precision of a float? ›- Reduce precision to gain performance.
- Reduce memory footprint.
- Round / floor arbitrarily.
- Make the number more "fuzzy"
- Reduce the number of digits after the coma.
A single-precision float only has about 7 decimal digits of precision (actually the log base 10 of 223, or about 6.92 digits of precision). The greater the integer part is, the less space is left for floating part precision.
Why should you not use the == operator to compare two floats? ›
Because even the smallest rounding error will cause two floating point numbers to not be equal, operator== is at high risk for returning false when a true might be expected. Operator!= has the same kind of problem. For this reason, use of these operators with floating point operands should generally be avoided.
Which is the most commonly used floating-point data type? ›The most commonly used floating point standard is the IEEE standard. According to this standard, floating point numbers are represented with 32 bits (single precision) or 64 bits (double precision).
Is comparing floating-point with == or != Unsafe? ›Conclusion. Do not under any circumstances use == or != to compare two float or double numbers. The comparison result will almost never be what you expect.
What is more precise than a float? ›Double is more precise than float and can store 64 bits, double of the number of bits float can store. Double is more precise and for storing large numbers, we prefer double over float.
Which is more accurate float or double? ›A variable of type float only has 7 digits of precision whereas a variable of type double has 15 digits of precision. If you need better accuracy, use double instead of float.
Is float more efficient than decimal? ›Decimal used within financial applications that require a high degree of accuracy and easy to avoid rounding errors whereas Float used when you stores scientific numbers and for better performance. Performance of Decimals is slower than and float data types.
What are the two advantages of float data type? ›Floating-point numbers have two advantages over integers. First, they can represent values between integers. Second, because of the scaling factor, they can represent a much greater range of values.
What is the precision of float vs double? ›A float has 7 decimal digits of precision and occupies 32 bits . A double is a 64-bit IEEE 754 double-precision floating-point number. 1 bit for the sign, 11 bits for the exponent, and 52 bits for the value. A double has 15 decimal digits of precision and occupies a total of 64 bits .
Are floats faster than doubles? ›Floats are faster than doubles when you don't need double's precision and you are memory-bandwidth bound and your hardware doesn't carry a penalty on floats. They conserve memory-bandwidth because they occupy half the space per number. There are also platforms that can process more floats than doubles in parallel.
How do I set decimal places in PHP? ›By default, number_format() uses a dot for the decimal point, and a comma for the thousands separator. To use different separators, pass the new decimal point separator as the third argument, and the new thousands separator as the fourth argument.
How to round to the nearest 1000 in PHP? ›
Use the round function as mentioned by other posters round($number, -3) . You can also, divide your number by 1,000, round to nearest whole number then multiply by 1,000. Also, if you want to round up, you can divide by 1,000, negate the quotient, coerce it to an integer, negate it again and then multiply it by 1,000.
What is the default precision in PHP? ›Although it depends on the system, PHP typically uses the IEEE 754 double precision format, which will give a maximum relative error due to rounding in the order of 1.11e-16.
How to round off to nearest 10 in PHP? ›- floor() rounds a number DOWN to the nearest integer if necessary.
- ceil() rounds a number UP to the nearest integer if necessary.
- round() rounds a number to specified precision (number of digits after the decimal point).
The is_float() function checks whether a variable is of type float or not. This function returns true (1) if the variable is of type float, otherwise it returns false.
How do you code 2 decimal places? ›Just use %. 2f as the format specifier. This will make the Java printf format a double to two decimal places.
How do you keep 2 decimal places? ›Rounding a decimal number to two decimal places is the same as rounding it to the hundredths place, which is the second place to the right of the decimal point. For example, 2.83620364 can be round to two decimal places as 2.84, and 0.7035 can be round to two decimal places as 0.70.
What is 4725 rounded to the nearest 1000? ›4,725 to the nearest 1,000 is 5,025 Page 9 A number is shown in the place value chart.
What is 4500 rounded to the nearest 1000? ›4,500 rounded to the nearest 1,000 is 5,000.
What is 7500 rounded to the nearest 1000? ›It is the same distance from each multiple of 1,000. When this happens, we have the AGREEMENT to round to the higher number; therefore, we agree 7,500 rounded to the "nearest thousand" is 8,000.
What is the limit of 64 bit floating-point? ›It has a minimum value of 0 and a maximum value of 4,294,967,295 (inclusive). A double-precision 64-bit IEEE 754 floating point.
What is the difference between float and decimal in PHP? ›
Float is a single precision (32 bit) floating point data type and decimal is a 128-bit floating point data type. Floating point data type represent number values with fractional parts.
What is 5.95 rounded to the nearest tenth? ›5.95 rounded to the nearest tenth is 6. 5.95 rounded to the nearest whole number is 6.
How to remove decimal without rounding in PHP? ›$rounded = floor($float*100)/100; Or you cast to integer: $rounded = 0.01 * (int)($float*100); This way it will not be rounding up.
How to round to a higher value in PHP? ›The ceil() function rounds a number UP to the nearest integer, if necessary. Tip: To round a number DOWN to the nearest integer, look at the floor() function.