Seen a few posts here and on reddit about how to change the settings concerning traders asking the same thing, I've also seen the same code suggestions used in several Mod's going around none of which use the features xpath provides. I won't post all the code just a few snippets.
First example is used to change the settings for just @id='1'
<set xpath="/traders/trader_info[@id='1']/@reset_interval">1</set>
<set xpath="/traders/trader_info[@id='1']/@min_inventory">40</set>
<set xpath="/traders/trader_info[@id='1']/@max_inventory">100</set>
<set xpath="/traders/trader_info[@id='1']/@min_items_swapped">40</set>
<set xpath="/traders/trader_info[@id='1']/@max_items_swapped">100</set>
<set xpath="/traders/trader_info[@id='1']/@open_time">0:00</set>
<set xpath="/traders/trader_info[@id='1']/@close_time">0:00</set>
Now if instead you use the features provided by xpath instead of redoing the above lines for @id='2', @id='6', @id='7' & @id='8' and having 7 lines for each ID
You can have just 7 lines instead of 35
<set xpath="/traders/trader_info[@id < 3 or @id > 5]/@reset_interval">1</set>
<set xpath="/traders/trader_info[@id < 3 or @id > 5]/@min_inventory">50</set>
<set xpath="/traders/trader_info[@id < 3 or @id > 5]/@max_inventory">100</set>
<set xpath="/traders/trader_info[@id < 3 or @id > 5]/@min_items_swapped">50</set>
<set xpath="/traders/trader_info[@id < 3 or @id > 5]/@max_items_swapped">100</set>
<set xpath="/traders/trader_info[@id < 3 or @id > 5]/@open_time">0:00</set>
<set xpath="/traders/trader_info[@id < 3 or @id > 5]/@close_time">0:00</set>
For played owned/rented vending machine ie @id'3' & @id'5' instead of 4 lines for both
<set xpath="/traders/trader_info[@id='3']/@reset_interval">1</set>
<set xpath="/traders/trader_info[@id='3']/@allow_sell">true</set>
<set xpath="/traders/trader_info[@id='5']/@reset_interval">1</set>
<set xpath="/traders/trader_info[@id='5']/@allow_sell">true</set>
You get the following 2 lines to cover both
<set xpath="/traders/trader_info[@id='3' or @id='5']/@reset_interval">1</set>
<set xpath="/traders/trader_info[@id='3' or @id='5']/@allow_sell">true</set>
Or if you don't want to type it all out here you go BG's Trader Fix