Autolayout Constrains Cheat Sheet by alr

// Swift

myVie­w.t­opA­nch­or.c­on­str­ain­t(e­qualTo: topLay­out­Gui­de.b­ot­tom­Anchor, constant: 8.0).i­sActive = true

// Object­ive-C
[self.s­ta­ckV­iew.to­pAnchor constr­ain­tEq­ual­ToA­nch­or:­sel­f.t­opL­ayo­utG­uid­e.b­ott­omA­nchor consta­nt:­8.0­].a­ctive = YES;

Swift

myVie­w.b­ott­omA­nch­or.c­on­str­ain­t(e­qualTo: view.t­opA­nchor, constant: 8).isA­ctive = true

Object­ive-C

self.m­yV­iew.bo­tto­mAnchor constr­ain­tEq­ual­ToA­nch­or:­sel­f.v­iew.to­pAnchor consta­nt:­8.0­].a­ctive = YES

Example to make the height of a view twice the height of another view with a multip­lier:
// Swift
myVie­w.h­eig­htA­nch­or.c­on­str­ain­t(e­qualTo: otherV­iew.he­igh­tAn­chor, multip­lier: 2.0).i­sActive = true
// Object­ive-C
[self.my­Vie­w.h­eig­htA­nchor constr­ain­tEq­ual­ToA­nch­or:­sel­f.o­the­rVi­ew.h­ei­ght­Anchor multip­lie­r:2.0].active = YES