TreeMap printout order

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chunji08@gmail.com - 08 Mar 2006 01:20 GMT

DATAs are being put in a TreeMap, how could I make sure that these
datas are being print out in the order they are read in ?

For example, I have datas as:
"07/20/2005", "NY",
"06/01/2005", "MA,
"01/01/2006", "CA".

The output should be the same as above, NOT
"01/01/2006", "CA".
"06/01/2005", "MA,
"07/20/2005", "NY",

I have tried different ways, no good. Help if you could !

cji

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Ian Pilcher - 08 Mar 2006 02:59 GMT

> DATAs are being put in a TreeMap, how could I make sure that these
> datas are being print out in the order they are read in ?
[quoted text clipped - 10 lines]
>
> I have tried different ways, no good. Help if you could !

Are you using Strings as keys? If so, the map will be sorted by the
lexical value of the Strings -- "01" < "06" < "07". You should be using
a class that handles dates more intelligently, such as Calendar.

HTH

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Ian Pilcher i.pilcher@comcast.net
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Roedy Green - 08 Mar 2006 03:53 GMT

On Tue, 07 Mar 2006 20:59:09 -0600, Ian Pilcher
<i.pilcher@comcast.net> wrote, quoted or indirectly quoted someone who
said :

>Are you using Strings as keys?

If you use ISO format yyyy-mm-dd you can get away with string
ordering.

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Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.

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John C. Bollinger - 08 Mar 2006 05:14 GMT

TreeMap will return keys, values, and entries in the relevant sort order
for the keys. If you want a Map implementation that returns all of
those in insertion order instead then you should consider LinkedHashMap.

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John Bollinger
jobollin@indiana.edu

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TreeMap printout order

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