m}  (Adverb)

The verb m} is (m&[}) : (m&{})
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u}  (Adverb)

ITEM AMEND (_)  u}y is an amendment of the items of y whose shape is the shape of an item of y. Each atom is selected as a corresponding atom in an item, the item being specified by the index in the corresponding position of u i.# y (whose shape must be the shape of an item of y). Thus:

   m=.0 1 3 1 2
   u=. m&{
	  y			       u i.}.$y
abcde			   0 1 3 1 2
fghij
klmno
pqrst
	  u}y			     m}y
agrio			   agrio
 
AMEND (_ _)  If x has the same shape as the index array j=. u i.$y, then x u} y amends x and y by  inserting the atoms of x in the selected positions of y. More generally, the shape of x may be a suffix of the shape of  j, and the result is an amendment of ($j) $ ,x and y. Thus, 'BD'1 3} 'abcd' is aBcD, and  if x=.'AGMS' and
u=.(<0 1)&|: (the diagonal verb), then u i.$y is 0 6 12 18, and:

	  y		      x u} u      'Z' u} y
abcde	 	 Abcde		     Zbcde
fghij		  fGhij		     fZhij
klmno		  klMno		     klZno
pqrst		  pqrSt		     pqrZs