Lua find a key from a value

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I'm working with this:

    chars = {

         ["Nigo Astran"]="1",

         ["pantera"]="2"

         }



   nchar = (chars[$name])+1

The variable $name will give me a string that I'm logged in to, in this case : "Nigo Astran"
and nchar has the value "2" if I'm in "Nigo Astran", and so on. I believe you get the idea.

Now, I want to get the key from the value, example:

when nchar is 2 it should give me "pantera" as the key. I'm just not getting the value of the key.

edited Jul 13 '15 at 13:05

ryanpattison

5,31011428

asked Oct 28 '11 at 4:14

Wesker

143129

add a comment |

I'm working with this:

    chars = {

         ["Nigo Astran"]="1",

         ["pantera"]="2"

         }



   nchar = (chars[$name])+1

The variable $name will give me a string that I'm logged in to, in this case : "Nigo Astran"
and nchar has the value "2" if I'm in "Nigo Astran", and so on. I believe you get the idea.

Now, I want to get the key from the value, example:

when nchar is 2 it should give me "pantera" as the key. I'm just not getting the value of the key.

edited Jul 13 '15 at 13:05

ryanpattison

5,31011428

asked Oct 28 '11 at 4:14

Wesker

143129

add a comment |

I'm working with this:

    chars = {

         ["Nigo Astran"]="1",

         ["pantera"]="2"

         }



   nchar = (chars[$name])+1

The variable $name will give me a string that I'm logged in to, in this case : "Nigo Astran"
and nchar has the value "2" if I'm in "Nigo Astran", and so on. I believe you get the idea.

Now, I want to get the key from the value, example:

when nchar is 2 it should give me "pantera" as the key. I'm just not getting the value of the key.

edited Jul 13 '15 at 13:05

ryanpattison

5,31011428

asked Oct 28 '11 at 4:14

Wesker

143129

I'm working with this:

    chars = {

         ["Nigo Astran"]="1",

         ["pantera"]="2"

         }



   nchar = (chars[$name])+1

The variable $name will give me a string that I'm logged in to, in this case : "Nigo Astran"
and nchar has the value "2" if I'm in "Nigo Astran", and so on. I believe you get the idea.

Now, I want to get the key from the value, example:

when nchar is 2 it should give me "pantera" as the key. I'm just not getting the value of the key.

lua

edited Jul 13 '15 at 13:05

ryanpattison

5,31011428

asked Oct 28 '11 at 4:14

Wesker

143129

edited Jul 13 '15 at 13:05

ryanpattison

5,31011428

asked Oct 28 '11 at 4:14

Wesker

143129

edited Jul 13 '15 at 13:05

ryanpattison

5,31011428

edited Jul 13 '15 at 13:05

ryanpattison

5,31011428

edited Jul 13 '15 at 13:05

ryanpattison

5,31011428

asked Oct 28 '11 at 4:14

Wesker

143129

asked Oct 28 '11 at 4:14

Wesker

143129

asked Oct 28 '11 at 4:14

Wesker

143129

add a comment |

3 Answers
3

active

oldest

votes

If you find yourself needing to get the key from the value of a table, consider inverting the table as in

function table_invert(t)

   local s={}

   for k,v in pairs(t) do

     s[v]=k

   end

   return s

end

edited Aug 31 '13 at 19:09

answered Oct 28 '11 at 10:08

lhf

56.7k668106

well atm im using this code function get_key_for_value( t, value ) for k,v in pairs(t) do if v==value then return k end return nil end now im finding another problem, when my table ends, and returns a nil i want it, to loop from the first value, cant do that yet <,<

– Wesker
Oct 28 '11 at 16:09

The for loop is missing a do.

– HeMan
Aug 31 '13 at 19:04

@HeMan, fixed, thanks.

– lhf
Aug 31 '13 at 19:09

add a comment |

I don't think there is anything more efficient than looping over the entries in the table using pairs and comparing the keys.

you can do that using something like this

function get_key_for_value( t, value )

  for k,v in pairs(t) do

    if v==value then return k end

  end

  return nil

end

Then you'd use it like this:

local k = get_key_for_value( chars, "1" )

edited Jan 4 at 4:37

Dale Burrell

3,47952655

answered Oct 28 '11 at 4:20

Michael Anderson

46.7k699150

ok that works but sadly, i cant do like <pre> nchar = (chars[$name])+1 <code> get_key_for_value( chars, nchar ) will be nil idk why, that was my problem at the start xD

– Wesker
Oct 28 '11 at 4:39

got it i did it with tostring() love you anyways <3

– Wesker
Oct 28 '11 at 4:58

add a comment |

-1

the best way to do that is like this

 local autoreply={

['hey']='hi',

['how are u']='am fine what about u?',

['how r u']='am fine what about u?',

['how are you']='am fine what about u?',

['sleep']='rockabye bayby good dreems',

['السلام']='وعليكم السلام ورحمة الله وبركاته',

}

local keys={'hey','how are u','how r u','how are you','sleep','السلام'}

function getValueFromKey(table,key)

  for k,v in ipairs(keys)do

  if string.find(string.upper(key),string.upper(v)) then return table[v] end

  end

   return false

end

answered Dec 18 '17 at 10:08

Master

add a comment |

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3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

If you find yourself needing to get the key from the value of a table, consider inverting the table as in

function table_invert(t)

   local s={}

   for k,v in pairs(t) do

     s[v]=k

   end

   return s

end

edited Aug 31 '13 at 19:09

answered Oct 28 '11 at 10:08

lhf

56.7k668106

well atm im using this code function get_key_for_value( t, value ) for k,v in pairs(t) do if v==value then return k end return nil end now im finding another problem, when my table ends, and returns a nil i want it, to loop from the first value, cant do that yet <,<

– Wesker
Oct 28 '11 at 16:09

The for loop is missing a do.

– HeMan
Aug 31 '13 at 19:04

@HeMan, fixed, thanks.

– lhf
Aug 31 '13 at 19:09

add a comment |

If you find yourself needing to get the key from the value of a table, consider inverting the table as in

function table_invert(t)

   local s={}

   for k,v in pairs(t) do

     s[v]=k

   end

   return s

end

edited Aug 31 '13 at 19:09

answered Oct 28 '11 at 10:08

lhf

56.7k668106

well atm im using this code function get_key_for_value( t, value ) for k,v in pairs(t) do if v==value then return k end return nil end now im finding another problem, when my table ends, and returns a nil i want it, to loop from the first value, cant do that yet <,<

– Wesker
Oct 28 '11 at 16:09

The for loop is missing a do.

– HeMan
Aug 31 '13 at 19:04

@HeMan, fixed, thanks.

– lhf
Aug 31 '13 at 19:09

add a comment |

If you find yourself needing to get the key from the value of a table, consider inverting the table as in

function table_invert(t)

   local s={}

   for k,v in pairs(t) do

     s[v]=k

   end

   return s

end

edited Aug 31 '13 at 19:09

answered Oct 28 '11 at 10:08

lhf

56.7k668106

If you find yourself needing to get the key from the value of a table, consider inverting the table as in

function table_invert(t)

   local s={}

   for k,v in pairs(t) do

     s[v]=k

   end

   return s

end

edited Aug 31 '13 at 19:09

answered Oct 28 '11 at 10:08

lhf

56.7k668106

edited Aug 31 '13 at 19:09

answered Oct 28 '11 at 10:08

lhf

56.7k668106

answered Oct 28 '11 at 10:08

lhf

56.7k668106

answered Oct 28 '11 at 10:08

lhf

56.7k668106

well atm im using this code function get_key_for_value( t, value ) for k,v in pairs(t) do if v==value then return k end return nil end now im finding another problem, when my table ends, and returns a nil i want it, to loop from the first value, cant do that yet <,<

– Wesker
Oct 28 '11 at 16:09

The for loop is missing a do.

– HeMan
Aug 31 '13 at 19:04

@HeMan, fixed, thanks.

– lhf
Aug 31 '13 at 19:09

add a comment |

well atm im using this code function get_key_for_value( t, value ) for k,v in pairs(t) do if v==value then return k end return nil end now im finding another problem, when my table ends, and returns a nil i want it, to loop from the first value, cant do that yet <,<

– Wesker
Oct 28 '11 at 16:09

The for loop is missing a do.

– HeMan
Aug 31 '13 at 19:04

@HeMan, fixed, thanks.

– lhf
Aug 31 '13 at 19:09

well atm im using this code function get_key_for_value( t, value ) for k,v in pairs(t) do if v==value then return k end return nil end now im finding another problem, when my table ends, and returns a nil i want it, to loop from the first value, cant do that yet <,<

– Wesker
Oct 28 '11 at 16:09

The for loop is missing a do.

– HeMan
Aug 31 '13 at 19:04

@HeMan, fixed, thanks.

– lhf
Aug 31 '13 at 19:09

add a comment |

I don't think there is anything more efficient than looping over the entries in the table using pairs and comparing the keys.

you can do that using something like this

function get_key_for_value( t, value )

  for k,v in pairs(t) do

    if v==value then return k end

  end

  return nil

end

Then you'd use it like this:

local k = get_key_for_value( chars, "1" )

edited Jan 4 at 4:37

Dale Burrell

3,47952655

answered Oct 28 '11 at 4:20

Michael Anderson

46.7k699150

ok that works but sadly, i cant do like <pre> nchar = (chars[$name])+1 <code> get_key_for_value( chars, nchar ) will be nil idk why, that was my problem at the start xD

– Wesker
Oct 28 '11 at 4:39

got it i did it with tostring() love you anyways <3

– Wesker
Oct 28 '11 at 4:58

add a comment |

I don't think there is anything more efficient than looping over the entries in the table using pairs and comparing the keys.

you can do that using something like this

function get_key_for_value( t, value )

  for k,v in pairs(t) do

    if v==value then return k end

  end

  return nil

end

Then you'd use it like this:

local k = get_key_for_value( chars, "1" )

edited Jan 4 at 4:37

Dale Burrell

3,47952655

answered Oct 28 '11 at 4:20

Michael Anderson

46.7k699150

ok that works but sadly, i cant do like <pre> nchar = (chars[$name])+1 <code> get_key_for_value( chars, nchar ) will be nil idk why, that was my problem at the start xD

– Wesker
Oct 28 '11 at 4:39

got it i did it with tostring() love you anyways <3

– Wesker
Oct 28 '11 at 4:58

add a comment |

I don't think there is anything more efficient than looping over the entries in the table using pairs and comparing the keys.

you can do that using something like this

function get_key_for_value( t, value )

  for k,v in pairs(t) do

    if v==value then return k end

  end

  return nil

end

Then you'd use it like this:

local k = get_key_for_value( chars, "1" )

edited Jan 4 at 4:37

Dale Burrell

3,47952655

answered Oct 28 '11 at 4:20

Michael Anderson

46.7k699150

I don't think there is anything more efficient than looping over the entries in the table using pairs and comparing the keys.

you can do that using something like this

function get_key_for_value( t, value )

  for k,v in pairs(t) do

    if v==value then return k end

  end

  return nil

end

Then you'd use it like this:

local k = get_key_for_value( chars, "1" )

edited Jan 4 at 4:37

Dale Burrell

3,47952655

answered Oct 28 '11 at 4:20

Michael Anderson

46.7k699150

edited Jan 4 at 4:37

Dale Burrell

3,47952655

edited Jan 4 at 4:37

Dale Burrell

3,47952655

edited Jan 4 at 4:37

Dale Burrell

3,47952655

answered Oct 28 '11 at 4:20

Michael Anderson

46.7k699150

answered Oct 28 '11 at 4:20

Michael Anderson

46.7k699150

answered Oct 28 '11 at 4:20

Michael Anderson

46.7k699150

ok that works but sadly, i cant do like <pre> nchar = (chars[$name])+1 <code> get_key_for_value( chars, nchar ) will be nil idk why, that was my problem at the start xD

– Wesker
Oct 28 '11 at 4:39

got it i did it with tostring() love you anyways <3

– Wesker
Oct 28 '11 at 4:58

add a comment |

ok that works but sadly, i cant do like <pre> nchar = (chars[$name])+1 <code> get_key_for_value( chars, nchar ) will be nil idk why, that was my problem at the start xD

– Wesker
Oct 28 '11 at 4:39

got it i did it with tostring() love you anyways <3

– Wesker
Oct 28 '11 at 4:58

ok that works but sadly, i cant do like <pre> nchar = (chars[$name])+1 <code> get_key_for_value( chars, nchar ) will be nil idk why, that was my problem at the start xD

– Wesker
Oct 28 '11 at 4:39

got it i did it with tostring() love you anyways <3

– Wesker
Oct 28 '11 at 4:58

add a comment |

-1

the best way to do that is like this

 local autoreply={

['hey']='hi',

['how are u']='am fine what about u?',

['how r u']='am fine what about u?',

['how are you']='am fine what about u?',

['sleep']='rockabye bayby good dreems',

['السلام']='وعليكم السلام ورحمة الله وبركاته',

}

local keys={'hey','how are u','how r u','how are you','sleep','السلام'}

function getValueFromKey(table,key)

  for k,v in ipairs(keys)do

  if string.find(string.upper(key),string.upper(v)) then return table[v] end

  end

   return false

end

answered Dec 18 '17 at 10:08

Master

add a comment |

-1

the best way to do that is like this

 local autoreply={

['hey']='hi',

['how are u']='am fine what about u?',

['how r u']='am fine what about u?',

['how are you']='am fine what about u?',

['sleep']='rockabye bayby good dreems',

['السلام']='وعليكم السلام ورحمة الله وبركاته',

}

local keys={'hey','how are u','how r u','how are you','sleep','السلام'}

function getValueFromKey(table,key)

  for k,v in ipairs(keys)do

  if string.find(string.upper(key),string.upper(v)) then return table[v] end

  end

   return false

end

answered Dec 18 '17 at 10:08

Master

add a comment |

-1

the best way to do that is like this

 local autoreply={

['hey']='hi',

['how are u']='am fine what about u?',

['how r u']='am fine what about u?',

['how are you']='am fine what about u?',

['sleep']='rockabye bayby good dreems',

['السلام']='وعليكم السلام ورحمة الله وبركاته',

}

local keys={'hey','how are u','how r u','how are you','sleep','السلام'}

function getValueFromKey(table,key)

  for k,v in ipairs(keys)do

  if string.find(string.upper(key),string.upper(v)) then return table[v] end

  end

   return false

end

answered Dec 18 '17 at 10:08

Master

the best way to do that is like this

 local autoreply={

['hey']='hi',

['how are u']='am fine what about u?',

['how r u']='am fine what about u?',

['how are you']='am fine what about u?',

['sleep']='rockabye bayby good dreems',

['السلام']='وعليكم السلام ورحمة الله وبركاته',

}

local keys={'hey','how are u','how r u','how are you','sleep','السلام'}

function getValueFromKey(table,key)

  for k,v in ipairs(keys)do

  if string.find(string.upper(key),string.upper(v)) then return table[v] end

  end

   return false

end

answered Dec 18 '17 at 10:08

Master

answered Dec 18 '17 at 10:08

Master

answered Dec 18 '17 at 10:08

Master

answered Dec 18 '17 at 10:08

Master

add a comment |

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