String#at (opens new window)

Returns a substring of a string object. Same interface as String#[].

String#from (opens new window)

Returns a substring from the given position to the end of the string.

String#to (opens new window)

Returns a substring from the beginning of the string to the given position.
If the position is negative, it is counted from the end of the string.

from and to can be used in tandem.

String#first (opens new window)

Returns the first character, or a given number of characters up to the length of the string.

String#last (opens new window)

Returns the last character, or a given number of characters from the end of the string counting backwards.

String#to_time (opens new window)

Converts a string to a Time value. The form parameter can be either :utc or :local, defaults to :local.

String#to_date (opens new window)

Converts a string to a Date value.

String#to_datetime (opens new window)

Converts a string to a DateTime value.

String#exclude? (opens new window)

The inverse of String#include?

String#squish (opens new window)

Returns a version of the given string without leading or trailing whitespace, and combines all consecutive whitespace in the interior to single spaces. Destructive version squish! operates directly on the string instance.

Handles both ASCII and Unicode whitespace.

This command does such and such.

Supported options are:
-h         This message
...

String#truncate (opens new window)

String#strip_heredoc (opens new window)

String#pluralize (opens new window)

Returns of plural form of the string. Optionally takes a count parameter and returns singular form if count == 1. Also accepts a locale parameter for language-specific pluralization.

String#singularize (opens new window)

Returns the singular form of the string. Accepts an optional locale parameter.

String#constantize (opens new window)

Tries to find a declared constant with the name specified in the string. It raises a NameError when the name is not in CamelCase or is not initialized.

String#safe_constantize (opens new window)

Performs a constantize but returns nil instead of raising NameError.

String#camelize (opens new window)

Converts strings to UpperCamelCase by default, if :lower is given as param converts to lowerCamelCase instead.

alias: camelcase

Note: will also convert / to :: which is useful for converting paths to namespaces.

String#titleize (opens new window)

Capitalizes all the words and replaces some characters in the string to create a nicer looking title.

alias: titlecase

String#underscore (opens new window)

Makes an underscored, lowercase form from the expression in the string. The reverse of camelize.

Note: underscore will also change :: to / to convert namespaces to paths.

String#dasherize (opens new window)

Replaces underscores with dashes in the string.

String#demodulize (opens new window)

Removes the module part from the constant expression in the string.

String#deconstantize (opens new window)

Removes the rightmost segment from the constant expression in the string.

String#parameterize (opens new window)

Replaces special characters in a string so that it may be used as part of a 'pretty' URL.

Preserve the case of the characters in a string with the :preserve_case argument.

A very common use-case for parameterize is to override the to_param method of an ActiveRecord model to support more descriptive url slugs.

String#tableize (opens new window)

Creates the name of a table like Rails does for models to table names. Pluralizes the last word in the string.

String#classify (opens new window)

Returns a class name string from a plural table name like Rails does for table names to models.

String#humanize (opens new window)

Capitalizes the first word, turns underscores into spaces, and strips a trailing _id if present.

String#upcase_first (opens new window)

Converts just the first character to uppercase.

String#foreign_key (opens new window)

Creates a foreign key name from a class name. Pass false param to disable adding _ between name and id.

Remarks

ActiveSupport is a utility gem of general-purpose tools used by the rest of the Rails framework.

One of the primary ways it provides these tools is by monkeypatching Ruby's native types. These are referred to as Core Extensions.