Should i go for i3-7th gen laptop or i5 laptop for android and web development?? Any suggestions

Depends, do you want to use an emulator and if yes, which one?
Also you should definitely have enough ram, otherwise you won't like android studio.

@glm9637 both have 4gb of ram

then none of them.
min requirments are 16gb ram, 256gb ssd, and a keyboard you can use. screen size, and weight are also considerations.
cpu speed, and gpu ranks very low on pro/con list, as the gains are very small in a similar price bracket.

@magicMirror can you suggest me a laptop in the range between 700$-750$

@SpiDee just look on retailer websites, they have more than enough filters to help you find a device to meet those requirements

@SpiDee sorry. at that price range, you will stare a the screen for a long time waiting for gradle to finish building things.

Doesn't matter as long as you have more than 4GB of ram. Get an SSD.

@SpiDee You can use android studio on a 4 GB ram device but it lags a lot. 6 GB ram and it lags when you run many windows at once. 8 GB ram runs android studio pretty smoothly. Tried all the 3 from above.I recommend you to get atleast 6 if not 8.