Since the Kernel module is included by Object class, its methods are available everywhere in the Ruby program. They can be called without a receiver (functional form). Therefore, they are often called functions.A complete list of Built-in Functions is given here for your reference −
Functions for Numbers
Here is a list of Built-in Functions related to number. They should be used as follows −Live Demo
#!/usr/bin/ruby num = 12.40 puts num.floor # 12 puts num + 10 # 22.40 puts num.integer? # false as num is a float.
This will produce the following result −
12 22.4 false
Assuming, n is a number −
Functions for Float
Here is a list of Ruby Built-in functions especially for float numbers. Assuming we have a float number f −
Functions for Math
Here is a list of Ruby Built-in math functions −
Conversion Field Specifier
The function sprintf( fmt[, arg…]) and format( fmt[, arg…]) returns a string in which arg is formatted according to fmt. Formatting specifications are essentially the same as those for sprintf in the C programming language. Conversion specifiers (% followed by conversion field specifier) in fmt are replaced by formatted string of corresponding argument.The following conversion specifiers are supported by Ruby’s format −
Following is the usage example −Live Demo
#!/usr/bin/ruby
str = sprintf("%s\n", "abc") # => "abc\n" (simplest form)
puts str
str = sprintf("d=%d", 42) # => "d=42" (decimal output)
puts str
str = sprintf("%04x", 255) # => "00ff" (width 4, zero padded)
puts str
str = sprintf("%8s", "hello") # => " hello" (space padded)
puts str
str = sprintf("%.2s", "hello") # => "he" (trimmed by precision)
puts str
This will produce the following result −
abc d = 42 00ff hello he
Test Function Arguments
The function test( test, f1[, f2]) performs one of the following file tests specified by the character test. In order to improve readability, you should use File class methods (for example, File::readable?) rather than this function.Here are the file tests with one argument −File tests with two arguments are as follows −
Following is the usage example. Assuming main.rb exist with read, write and not execute permissions −Live Demo
#!/usr/bin/ruby puts test(?r, "main.rb" ) # => true puts test(?w, "main.rb" ) # => true puts test(?x, "main.rb" ) # => false
This will produce the following result −
true false false