Returns a String containing the generated JSON data.
See also JSON.fast_generate, JSON.pretty_generate.
Argument obj is the Ruby object to be converted to JSON.
Argument opts, if given, contains a Hash of options for the generation. See Generating Options.
When obj is an Array, returns a String containing a JSON array:
obj = ["foo", 1.0, true, false, nil] json = JSON.generate(obj) json # => '["foo",1.0,true,false,null]'
When obj is a Hash, returns a String containing a JSON object:
obj = {foo: 0, bar: 's', baz: :bat} json = JSON.generate(obj) json # => '{"foo":0,"bar":"s","baz":"bat"}'
For examples of generating from other Ruby objects, see Generating JSON from Other Objects.
Raises an exception if any formatting option is not a String.
Raises an exception if obj contains circular references:
a = []; b = []; a.push(b); b.push(a) # Raises JSON::NestingError (nesting of 100 is too deep): JSON.generate(a)
Returns the fractional part of the day in range (Rational(0, 1)…Rational(1, 1)):
DateTime.new(2001,2,3,12).day_fraction # => (1/2)
Equivalent to Date#+ with argument n.
Equivalent to >> with argument n * 12.
Returns true if matching against re can be done in linear time to the input string.
Regexp.linear_time?(/re/) # => true
Note that this is a property of the ruby interpreter, not of the argument regular expression. Identical regexp can or cannot run in linear time depending on your ruby binary. Neither forward nor backward compatibility is guaranteed about the return value of this method. Our current algorithm is (*1) but this is subject to change in the future. Alternative implementations can also behave differently. They might always return false for everything.
Returns the data created by parsing the first line of string or io using the specified options.
Argument string should be a String object; it will be put into a new StringIO object positioned at the beginning.
Argument io should be an IO object that is:
Open for reading; on return, the IO object will be closed.
Positioned at the beginning. To position at the end, for appending, use method CSV.generate. For any other positioning, pass a preset StringIO object instead.
Argument options: see Options for Parsing
headers Without option headers, returns the first row as a new Array.
These examples assume prior execution of:
string = "foo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string)
Parse the first line from a String object:
CSV.parse_line(string) # => ["foo", "0"]
Parse the first line from a File object:
File.open(path) do |file| CSV.parse_line(file) # => ["foo", "0"] end # => ["foo", "0"]
Returns nil if the argument is an empty String:
CSV.parse_line('') # => nil
headers With {option headers}, returns the first row as a CSV::Row object.
These examples assume prior execution of:
string = "Name,Count\nfoo,0\nbar,1\nbaz,2\n" path = 't.csv' File.write(path, string)
Parse the first line from a String object:
CSV.parse_line(string, headers: true) # => #<CSV::Row "Name":"foo" "Count":"0">
Parse the first line from a File object:
File.open(path) do |file| CSV.parse_line(file, headers: true) end # => #<CSV::Row "Name":"foo" "Count":"0">
Raises an exception if the argument is nil:
# Raises ArgumentError (Cannot parse nil as CSV): CSV.parse_line(nil)
Returns the value that determines whether illegal input is to be handled; used for parsing; see {Option liberal_parsing}:
CSV.new('').liberal_parsing? # => false
Controls tracing of assignments to global variables. The parameter symbol identifies the variable (as either a string name or a symbol identifier). cmd (which may be a string or a Proc object) or block is executed whenever the variable is assigned. The block or Proc object receives the variable’s new value as a parameter. Also see Kernel::untrace_var.
trace_var :$_, proc {|v| puts "$_ is now '#{v}'" } $_ = "hello" $_ = ' there'
produces:
$_ is now 'hello' $_ is now ' there'
Removes tracing for the specified command on the given global variable and returns nil. If no command is specified, removes all tracing for that variable and returns an array containing the commands actually removed.
Arguments obj and opts here are the same as arguments obj and opts in JSON.generate.
By default, generates JSON data without checking for circular references in obj (option max_nesting set to false, disabled).
Raises an exception if obj contains circular references:
a = []; b = []; a.push(b); b.push(a) # Raises SystemStackError (stack level too deep): JSON.fast_generate(a)
Arguments obj and opts here are the same as arguments obj and opts in JSON.generate.
Default options are:
{
indent: ' ', # Two spaces
space: ' ', # One space
array_nl: "\n", # Newline
object_nl: "\n" # Newline
}
Example:
obj = {foo: [:bar, :baz], bat: {bam: 0, bad: 1}} json = JSON.pretty_generate(obj) puts json
Output:
{
"foo": [
"bar",
"baz"
],
"bat": {
"bam": 0,
"bad": 1
}
}
Returns garbage collector generation for the given object.
class B include ObjectSpace def foo trace_object_allocations do obj = Object.new p "Generation is #{allocation_generation(obj)}" end end end B.new.foo #=> "Generation is 3"
See ::trace_object_allocations for more information and examples.
How String Gem paths should be split. Overridable for esoteric platforms.
Adds DidYouMean functionality to an error using a given spell checker
Returns whether or not the given entry point func can be found within lib. If func is nil, the main() entry point is used by default. If found, it adds the library to list of libraries to be used when linking your extension.
If headers are provided, it will include those header files as the header files it looks in when searching for func.
The real name of the library to be linked can be altered by --with-FOOlib configuration option.
Returns whether or not the entry point func can be found within the library lib in one of the paths specified, where paths is an array of strings. If func is nil , then the main() function is used as the entry point.
If lib is found, then the path it was found on is added to the list of library paths searched and linked against.
Returns whether or not the given framework can be found on your system. If found, a macro is passed as a preprocessor constant to the compiler using the framework name, in uppercase, prepended with HAVE_FRAMEWORK_.
For example, if have_framework('Ruby') returned true, then the HAVE_FRAMEWORK_RUBY preprocessor macro would be passed to the compiler.
If fw is a pair of the framework name and its header file name that header file is checked, instead of the normally used header file which is named same as the framework.
Returns the signedness of the given type. You may optionally specify additional headers to search in for the type.
If the type is found and is a numeric type, a macro is passed as a preprocessor constant to the compiler using the type name, in uppercase, prepended with SIGNEDNESS_OF_, followed by the type name, followed by =X where “X” is positive integer if the type is unsigned and a negative integer if the type is signed.
For example, if size_t is defined as unsigned, then check_signedness('size_t') would return +1 and the SIGNEDNESS_OF_SIZE_T=+1 preprocessor macro would be passed to the compiler. The SIGNEDNESS_OF_INT=-1 macro would be set for check_signedness('int')
Basically a wrapper for Process.spawn that:
Creates a child process for each of the given cmds by calling Process.spawn.
Does not wait for child processes to exit.
With no block given, returns an array of the wait threads for all of the child processes.
Example:
wait_threads = Open3.pipeline_start('ls', 'grep R') # => [#<Process::Waiter:0x000055e8de9d2bb0 run>, #<Process::Waiter:0x000055e8de9d2890 run>] wait_threads.each do |wait_thread| wait_thread.join end
Output:
Rakefile README.md
With a block given, calls the block with an array of the wait processes:
Open3.pipeline_start('ls', 'grep R') do |wait_threads| wait_threads.each do |wait_thread| wait_thread.join end end
Output:
Rakefile README.md
Like Process.spawn, this method has potential security vulnerabilities if called with untrusted input; see Command Injection.
If the first argument is a hash, it becomes leading argument env in each call to Process.spawn; see Execution Environment.
If the last argument is a hash, it becomes trailing argument options in each call to Process.spawn; see Execution Options.
Each remaining argument in cmds is one of:
A command_line: a string that begins with a shell reserved word or special built-in, or contains one or more metacharacters.
An exe_path: the string path to an executable to be called.
An array containing a command_line or an exe_path, along with zero or more string arguments for the command.
Basically a wrapper for Process.spawn that:
Creates a child process for each of the given cmds by calling Process.spawn.
Does not wait for child processes to exit.
With no block given, returns an array of the wait threads for all of the child processes.
Example:
wait_threads = Open3.pipeline_start('ls', 'grep R') # => [#<Process::Waiter:0x000055e8de9d2bb0 run>, #<Process::Waiter:0x000055e8de9d2890 run>] wait_threads.each do |wait_thread| wait_thread.join end
Output:
Rakefile README.md
With a block given, calls the block with an array of the wait processes:
Open3.pipeline_start('ls', 'grep R') do |wait_threads| wait_threads.each do |wait_thread| wait_thread.join end end
Output:
Rakefile README.md
Like Process.spawn, this method has potential security vulnerabilities if called with untrusted input; see Command Injection.
If the first argument is a hash, it becomes leading argument env in each call to Process.spawn; see Execution Environment.
If the last argument is a hash, it becomes trailing argument options in each call to Process.spawn; see Execution Options.
Each remaining argument in cmds is one of:
A command_line: a string that begins with a shell reserved word or special built-in, or contains one or more metacharacters.
An exe_path: the string path to an executable to be called.
An array containing a command_line or an exe_path, along with zero or more string arguments for the command.