The IPlayer interface allows you to view certain information on a specific player and interact with said one. Mostly used in Event Handlers and Recipe Functions.

It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import.
import crafttweaker.player.IPlayer;

IPlayer extends IEntityLivingBase. That means all functions available to IEntityLivingBase Objects also are available to IPlayer Objects.
IPlayer also extends IUser. That means all functions available to IUser Objects also are available to IPlayer Objects.

Zengetters are for retrieving information. Usually either assigned to a variable or used in a method/function.

Геттер	What does it do	Возвращаемый тип	Usage
Геттер uuid	What does it do возвращает UUID игрока	Возвращаемый тип string	Usage игрок.uuid
Геттер name	What does it do returns the player's name	Возвращаемый тип string	Usage player.name
Геттер data	What does it do returns the player's data	Возвращаемый тип IData	Usage player.data
Геттер xp	What does it do returns the player's experience level. Can also be used to set a player's experience level	Возвращаемый тип int	Usage player.xp
Геттер hotbarSize	What does it do returns the player's hotbar size	Возвращаемый тип int	Usage player.hotbarSize
Геттер inventorySize	What does it do returns the player's inventory size	Возвращаемый тип int	Usage player.inventorySize
Геттер currentItem	What does it do returns the item the player is currently holding	Возвращаемый тип IItemStack	Usage player.currentItem
Геттер creative	What does it do returns if the player is currently in creative mode (a.k.a gamemode 1)	Возвращаемый тип bool	Usage player.creative
Геттер adventure	What does it do returns if the player is currently in adventure mode (a.k.a gamemode 2)	Возвращаемый тип bool	Usage player.adventure
Геттер x	What does it do returns the player's current X position in the world	Возвращаемый тип double	Usage player.x
Геттер y	What does it do returns the player's current y position in the world	Возвращаемый тип double	Usage player.y
Геттер z	What does it do returns the player's current z position in the world	Возвращаемый тип double	Usage player.z
Геттер position	What does it do returns the player's current position. Can also be used to set a player's position	Возвращаемый тип Position3f	Usage player.position
Геттер foodStats	What does it do returns the player's foodstats.	Возвращаемый тип IFoodStats	Usage player.foodStats
Геттер bedLocation	What does it do returns the location of the player's bed.	Возвращаемый тип IBlockPos	Usage player.bedLocation
Геттер fishHook	What does it do returns the player's fishingrod entity.	Возвращаемый тип [IEntityFishHook ](/Vanilla/Entities/IEntityFishHook /)	Usage player.fishHook
Геттер foodStats	What does it do returns the player's foodstats.	Возвращаемый тип IFoodStats	Usage player.foodStats

Методы ZenMethods для действий с другими вещами, в этом случае с игроком.

ZenMethod	Parameter Type(s)	What does it do	Пример
ZenMethod removeXP(XPtoRemove)	Parameter Type(s) int	What does it do Removes the given experience levels from the player.	Пример player.removeXP(1)
ZenMethod update(IData)	Parameter Type(s) IData	What does it do Updates the playerdata to the provided IData.	Пример ​
ZenMethod sendChat(Message)	Parameter Type(s) string OR IChatMessage	What does it do Sends the player a Chat Message.	Пример player.sendChat("Hello my old friend")
ZenMethod sendStatusMessage(message, hotbar)	Parameter Type(s) string OR IFormattedText	What does it do Sends the player a status message, if the hotbar argument is true, the message will be displayed on player's hotbar, the default value is true	Пример player.sendStatusMessage("hello, world")
ZenMethod sendRichTextStatusMessage(message, hotbar)	Parameter Type(s) ITextComponent	What does it do same as sendStatusMessage, but the message is an ITextComponent	Пример ​
ZenMethod getHotbarStack(index)	Parameter Type(s) int	What does it do Returns the item at the given index within the player's hotbar.	Пример player.getHotbarStack(3)
ZenMethod getInventoryStack(index)	Parameter Type(s) int	What does it do Returns the item at the given index within the player's inventory.	Пример player.getInventoryStack(3)
ZenMethod give(item)	Parameter Type(s) IItemStack	What does it do Give the player the provided item. Предмет имеет тип IItemStack.	Пример player.give(<minecraft:gold_ingot>)
ZenMethod teleport(position)	Parameter Type(s) Position3f	What does it do Teleports the player to the provided position in the same dimension	Пример player.teleport(position)
ZenMethod executeCommand(raw)	Parameter Type(s) string	What does it do Executes the command as the player	Пример player.executeCommand("kill")
ZenMethod dropItem(dropAll)	Parameter Type(s) bool	What does it do Drops the current item (or the entire stack) that the player is holding.	Пример player.dropItem(false)
ZenMethod dropItem(itemToDrop)	Parameter Type(s) IItemStack	What does it do Drops the provided item at the player's position.	Пример player.dropItem(<minecraft:dirt>)
ZenMethod getCooldown(item)	Parameter Type(s) IItemStack	What does it do Gets current cooldown of specific item for the player	Пример player.getCooldown(<minecraft:ender_pearl>)
ZenMethod setCooldown(item, time)	Parameter Type(s) IItemStack, int	What does it do Sets cooldown time of specific item for the player	Пример player.setCooldown(<minecraft:ender_pearl>, 3)