How do I connect an Arduino Uno and Raspberry Pi via Wifi?

So I have this little project going on which is a Wireless Sensor Network using a Raspberry Pi and Arduino UNO. I have a Wireless shield for my UNO but I'm still confused. What I want to do is collect data using the UNO then send it to the Pi. Can anyone show me how to do this?

Like can you make or show me a guide on how to connect and program this thing?

P.S. I'm a little new to the Arduino's Wireless Shield but I do know how to use the UNO and Pi...Ples Halp in the name of Lord Gaben!

Do you have a local WLan which you can use?

Is your Pi attached to it (if WLAN available)?

Do you have a WiFi extension on/for the Pi (if no WLAN available)?

Yes, I have Arduino with wifi module and Raspberry Pi 3 with wifi integrated (with Windows 10 IoT).

How I can transfer data from Arduino sensor to Raspberry App?.

IMHO I think it would be easier to transmit data via Bluetooth instead of WiFi. RPi3 units come with built in Bluetooth.

Power_Broker:
IMHO I think it would be easier to transmit data via Bluetooth instead of WiFi. RPi3 units come with built in Bluetooth.

If possible, I would use a serial protocol instead of Bluetooth. I think the wireless connection is never as stable as wired connection like serial, SPI, I2C ... But if wireless is only choice, it could be wifi for easy to integrate with other stuffs.

vwy5:
If possible, I would use a serial protocol instead of Bluetooth. I think the wireless connection is never as stable as wired connection like serial, SPI, I2C … But if wireless is only choice, it could be wifi for easy to integrate with other stuffs.

Not to sound mean, but what the heck are you talking about? Bluetooth IS a serial standard and is governed by the IEEE. You hook it up to a UART serial port and treat it like any standard UART serial communication.