Is There a Better Way of Checking Nil or Length 0 of a String in Ruby

Question

Is there a better way than the following to check to see if a string is nil OR has a length of 0 in Ruby   if  my string    my string length    0   return true else   return false end   In C  there s the handy  string IsNullOrEmpty myString    Anything similar to that in Ruby

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If you are using rails  you can use  present   require  rails   nil present        gt  false  Works on nil     present          gt  false  Works on strings       present        gt  false  Works on blank strings     present          gt  false Works on arrays  false present       gt  false  Works on boolean    So  conversely to check for nil or zero length use  present     nil present         gt  true      present           gt  true        present         gt  true      present           gt  true   false present        gt  true

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variable blank  will do it  It returns true if the string is empty or if the string is nil

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As it was said here before Rails  ActiveSupport  have a handy blank  method and it is implemented like this   class Object   def blank      respond to   empty     empty     self   end end   Pretty easy to add to any ruby-based project   The beauty of this solution is that it works auto-magicaly not only for Strings but also for Arrays and other types

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In rails you can try  blank    Warning  it will give you positives when string consists of spaces   nil blank       gt  true    blank       gt  true      blank       gt  true  false  blank       gt  false   Just wanted to point it out  Maybe it suits your needs  UPD  why am i getting old questions in my feed  Sorry for necroposting

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nil  can be omitted in boolean contexts  Generally  you can use this to replicate the C  code   return my string nil      my string empty

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I like to do this as follows  in a non Rails ActiveSupport environment    variable to s empty    this works because   nil to s          to s

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If you are using rails  you can use  present   require  rails   nil present        gt  false  Works on nil     present          gt  false  Works on strings       present        gt  false  Works on blank strings     present          gt  false Works on arrays  false present       gt  false  Works on boolean    So  conversely to check for nil or zero length use  present     nil present         gt  true      present           gt  true        present         gt  true      present           gt  true   false present        gt  true

User · Answer

variable blank  will do it  It returns true if the string is empty or if the string is nil

User · Answer

When I m not worried about performance  I ll often use this   if my string to s           It s nil or empty end   There are various variations  of course     if my string to s strip length    0     It s nil  empty  or just whitespace end

User · Answer

First of all  beware of that method   As Jesse Ezel says      Brad Abrams            The method might seem convenient  but most of the time I have found that this situation arises from trying to cover up deeper bugs          Your code should stick to a particular protocol on the use of strings  and you should understand the use of the protocol in library code and in the code you are working with       The NullOrEmpty protocol is typically a quick fix  so the real problem is still somewhere else  and you got two protocols in use  or it is a lack of expertise in a particular protocol when implementing new code  and again  you should really know what your return values are      And if you patch String class    be sure NilClass has not been patch either   class NilClass     def empty   true  end end

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Have you tried Refinements   module Nothingness   refine String do     alias method  nothing    empty    end    refine NilClass do     alias method  nothing    nil    end end  using Nothingness  return my string nothing

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For code golfers   if my string        p  non-empty string  else   p  nil or empty string  end   Or if you re not a golfer  requires ruby 2 3 or later    if my string amp  size amp  positive      nonzero  also works   p  non-empty string  else   p  nil or empty string  end

User · Answer

Every class has a nil  method   if a variable nil        the variable has a nil value end   And strings have the empty  method   if a string empty        the string is empty     Remember that a string does not equal nil when it is empty  so use the empty  method to check if a string is empty

User · Answer

Every class has a nil  method   if a variable nil        the variable has a nil value end   And strings have the empty  method   if a string empty        the string is empty     Remember that a string does not equal nil when it is empty  so use the empty  method to check if a string is empty

User · Answer

Check for Empty Strings in Plain Ruby While Avoiding NameError Exceptions  There are some good answers here  but you don t need ActiveSupport or monkey-patching to address the common use case here  For example   my string to s empty  if defined  my string   This will  do the right thing  if my string is nil or an empty string  but will not raise a NameError exception if my string is not defined  This is generally preferable to the more contrived   my string to s empty  rescue NameError   or its more verbose ilk  because exceptions should really be saved for things you don t expect to happen  In this case  while it might be a common error  an undefined variable isn t really an exceptional circumstance  so it should be handled accordingly   Your mileage may vary

User · Answer

nil  can be omitted in boolean contexts  Generally  you can use this to replicate the C  code   return my string nil      my string empty

User · Answer

As it was said here before Rails  ActiveSupport  have a handy blank  method and it is implemented like this   class Object   def blank      respond to   empty     empty     self   end end   Pretty easy to add to any ruby-based project   The beauty of this solution is that it works auto-magicaly not only for Strings but also for Arrays and other types

User · Answer

As it was said here before Rails  ActiveSupport  have a handy blank  method and it is implemented like this   class Object   def blank      respond to   empty     empty     self   end end   Pretty easy to add to any ruby-based project   The beauty of this solution is that it works auto-magicaly not only for Strings but also for Arrays and other types

User · Answer

nil  can be omitted in boolean contexts  Generally  you can use this to replicate the C  code   return my string nil      my string empty

User · Answer

Every class has a nil  method   if a variable nil        the variable has a nil value end   And strings have the empty  method   if a string empty        the string is empty     Remember that a string does not equal nil when it is empty  so use the empty  method to check if a string is empty

User · Answer

I like to do this as follows  in a non Rails ActiveSupport environment    variable to s empty    this works because   nil to s          to s

User · Answer

If you are willing to require ActiveSupport you can just use the  blank  method  which is defined for both NilClass and String

User · Answer

In rails you can try  blank    Warning  it will give you positives when string consists of spaces   nil blank       gt  true    blank       gt  true      blank       gt  true  false  blank       gt  false   Just wanted to point it out  Maybe it suits your needs  UPD  why am i getting old questions in my feed  Sorry for necroposting

User · Answer

First of all  beware of that method   As Jesse Ezel says      Brad Abrams            The method might seem convenient  but most of the time I have found that this situation arises from trying to cover up deeper bugs          Your code should stick to a particular protocol on the use of strings  and you should understand the use of the protocol in library code and in the code you are working with       The NullOrEmpty protocol is typically a quick fix  so the real problem is still somewhere else  and you got two protocols in use  or it is a lack of expertise in a particular protocol when implementing new code  and again  you should really know what your return values are      And if you patch String class    be sure NilClass has not been patch either   class NilClass     def empty   true  end end

User · Answer

Konrad Rudolph has the right answer   If it really bugs you  monkey patch the String class or add it to a class module of your choice   It s really not a good practice to monkey patch core objects unless you have a really compelling reason though   class String   def self nilorempty  string      string nil     string empty    end end   Then you can do String nilorempty  mystring

User · Answer

An alternative to jcoby s proposal would be   class NilClass   def nil or empty      true   end end  class String   def nil or empty      empty    end end

User · Answer

Check for Empty Strings in Plain Ruby While Avoiding NameError Exceptions  There are some good answers here  but you don t need ActiveSupport or monkey-patching to address the common use case here  For example   my string to s empty  if defined  my string   This will  do the right thing  if my string is nil or an empty string  but will not raise a NameError exception if my string is not defined  This is generally preferable to the more contrived   my string to s empty  rescue NameError   or its more verbose ilk  because exceptions should really be saved for things you don t expect to happen  In this case  while it might be a common error  an undefined variable isn t really an exceptional circumstance  so it should be handled accordingly   Your mileage may vary

User · Answer

First of all  beware of that method   As Jesse Ezel says      Brad Abrams            The method might seem convenient  but most of the time I have found that this situation arises from trying to cover up deeper bugs          Your code should stick to a particular protocol on the use of strings  and you should understand the use of the protocol in library code and in the code you are working with       The NullOrEmpty protocol is typically a quick fix  so the real problem is still somewhere else  and you got two protocols in use  or it is a lack of expertise in a particular protocol when implementing new code  and again  you should really know what your return values are      And if you patch String class    be sure NilClass has not been patch either   class NilClass     def empty   true  end end

User · Answer

Konrad Rudolph has the right answer   If it really bugs you  monkey patch the String class or add it to a class module of your choice   It s really not a good practice to monkey patch core objects unless you have a really compelling reason though   class String   def self nilorempty  string      string nil     string empty    end end   Then you can do String nilorempty  mystring

User · Answer

Konrad Rudolph has the right answer   If it really bugs you  monkey patch the String class or add it to a class module of your choice   It s really not a good practice to monkey patch core objects unless you have a really compelling reason though   class String   def self nilorempty  string      string nil     string empty    end end   Then you can do String nilorempty  mystring

User · Answer

As it was said here before Rails  ActiveSupport  have a handy blank  method and it is implemented like this   class Object   def blank      respond to   empty     empty     self   end end   Pretty easy to add to any ruby-based project   The beauty of this solution is that it works auto-magicaly not only for Strings but also for Arrays and other types

User · Answer

First of all  beware of that method   As Jesse Ezel says      Brad Abrams            The method might seem convenient  but most of the time I have found that this situation arises from trying to cover up deeper bugs          Your code should stick to a particular protocol on the use of strings  and you should understand the use of the protocol in library code and in the code you are working with       The NullOrEmpty protocol is typically a quick fix  so the real problem is still somewhere else  and you got two protocols in use  or it is a lack of expertise in a particular protocol when implementing new code  and again  you should really know what your return values are      And if you patch String class    be sure NilClass has not been patch either   class NilClass     def empty   true  end end

User · Answer

When I m not worried about performance  I ll often use this   if my string to s           It s nil or empty end   There are various variations  of course     if my string to s strip length    0     It s nil  empty  or just whitespace end

User · Answer

When I m not worried about performance  I ll often use this   if my string to s           It s nil or empty end   There are various variations  of course     if my string to s strip length    0     It s nil  empty  or just whitespace end

User · Answer

Every class has a nil  method   if a variable nil        the variable has a nil value end   And strings have the empty  method   if a string empty        the string is empty     Remember that a string does not equal nil when it is empty  so use the empty  method to check if a string is empty

User · Answer

An alternative to jcoby s proposal would be   class NilClass   def nil or empty      true   end end  class String   def nil or empty      empty    end end

User · Answer

If you are willing to require ActiveSupport you can just use the  blank  method  which is defined for both NilClass and String

User · Answer

For code golfers   if my string        p  non-empty string  else   p  nil or empty string  end   Or if you re not a golfer  requires ruby 2 3 or later    if my string amp  size amp  positive      nonzero  also works   p  non-empty string  else   p  nil or empty string  end

User · Answer

An alternative to jcoby s proposal would be   class NilClass   def nil or empty      true   end end  class String   def nil or empty      empty    end end

User · Answer

Another option is to convert nil to an empty result on the fly    my string      empty

User · Answer

If you are willing to require ActiveSupport you can just use the  blank  method  which is defined for both NilClass and String

User · Answer

If you are willing to require ActiveSupport you can just use the  blank  method  which is defined for both NilClass and String

User · Answer

Another option is to convert nil to an empty result on the fly    my string      empty

User · Answer

Have you tried Refinements   module Nothingness   refine String do     alias method  nothing    empty    end    refine NilClass do     alias method  nothing    nil    end end  using Nothingness  return my string nothing

User · Answer

When I m not worried about performance  I ll often use this   if my string to s           It s nil or empty end   There are various variations  of course     if my string to s strip length    0     It s nil  empty  or just whitespace end

User · Answer

nil  can be omitted in boolean contexts  Generally  you can use this to replicate the C  code   return my string nil      my string empty

User · Answer

An alternative to jcoby s proposal would be   class NilClass   def nil or empty      true   end end  class String   def nil or empty      empty    end end

User · Answer

Konrad Rudolph has the right answer   If it really bugs you  monkey patch the String class or add it to a class module of your choice   It s really not a good practice to monkey patch core objects unless you have a really compelling reason though   class String   def self nilorempty  string      string nil     string empty    end end   Then you can do String nilorempty  mystring

[ruby] Is There a Better Way of Checking Nil or Length == 0 of a String in Ruby?

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