MAP index

gpe · Oct 29, 2011

I noticed that in MAP collection the member "indexOf" is missing.
Is there a way to find out the index related to the key other than searching among the items?
gp

Erel · Oct 30, 2011

You will need to search among the items.

The index is usually less important in Maps. The index is only available to allow you to iterate over the items.

gpe · Oct 30, 2011

many thanks, Erel
I need to filter an array of strings where the key is inside and build a listview.
I'm not so sure, but creating a map using substrings doesn't work properly. This is the reason I wanted to use the index instead of keys.
Now I've solved the problem creating two arrays to correlate the indexes.

Hubert Brandel · Oct 30, 2011

Is this a bug ?

Hi,

map keys are unique, this is true and usefull.
It works good with numeric keys, but I was confused on this:

B4X:

Dim m As Map
m.Initialize
m.Put("test","Testwert")
m.Put("TEST","New Value")
Log("Test=" &  m.Get("Test") ) ' => null
Log("test=" &  m.Get("test") ) ' => Testwert
Log("TEST=" &  m.Get("Test") ) ' => null

The seconds call - m.Put("TEST","New Value") - was ignored.
m.GET is case sensitive, thats not usefull.
PUT should build the key with key.tolower()
GET should build the key with key.equalignorecases()

Am I right ?

Does SQL needs fieldnames in lower ?

klaus · Oct 30, 2011

The second Put statement was shurely not ignored!
You didn't look at it right:
Your last Log should be like this:

B4X:

Log("T[COLOR=Black]EST[/COLOR]"=" & m.Get("T[COLOR=Red]EST[/COLOR]"))

Best regards.

agraham · Oct 30, 2011

Hubert Brandel said:
PUT should build the key with key.tolower()
GET should build the key with key.equalignorecases()

Am I right ?

No. A Map can hold any kind of Object for keys and values, not just Strings. A Map just tests for object identity, it knows nothing about what the actual keys and values are. If you are using string you will have to do your own case-conversion if you want case-insensitivity.

Erel · Oct 30, 2011

object identity

=> object equality.

Hubert Brandel · Oct 31, 2011

Hi,

@ Klaus,

you are right and found my mistake

B4X:

Dim m As Map
m.Initialize
m.Put("test","Testwert")
m.Put("TEST","New Value")
Log("Test=" &  m.Get("Test") ) ' => null
Log("test=" &  m.Get("test") ) ' => Testwert
Log("TEST=" &  m.Get("TEST") ) ' => "New Value"

@all

I find it very strange to have case sensitive variables and filenames. I can't see any serious reason why linux does it this way. A case insensitive
key would be much easier and avoid typing errors.

kickaha · Oct 31, 2011

Hubert Brandel said:
Hi,
@all

I find it very strange to have case sensitive variables and filenames. I can't see any serious reason why linux does it this way. A case insensitive
key would be much easier and avoid typing errors.

Yes but it would not be as flexible (and therefore not as useful).

MAP index

gpe

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gpe

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klaus

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Erel

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Hubert Brandel

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