FlattenAt [list,n]
flattens out a sublist that appears as the nth element of list. If n is negative, the position is counted from the end.
FlattenAt [expr,{i,j,…}]
flattens out the part of expr at position {i,j,…}.
FlattenAt [expr,{{i1,j1,…},{i2,j2,…},…}]
flattens out parts of expr at several positions.
FlattenAt
FlattenAt [list,n]
flattens out a sublist that appears as the nth element of list. If n is negative, the position is counted from the end.
FlattenAt [expr,{i,j,…}]
flattens out the part of expr at position {i,j,…}.
FlattenAt [expr,{{i1,j1,…},{i2,j2,…},…}]
flattens out parts of expr at several positions.
Examples
open all close allBasic Examples (2)
Flatten at position 2:
Flatten at positions 2 and 4:
Scope (3)
FlattenAt can splice the arguments of any expression, not just lists:
Consider a matrix:
Flatten the first element (row) of the matrix:
Equivalently:
Flatten at position 1,2 (the element in the first row, second column):
Flatten at positions 1 and 2 (the rows) of the matrix:
Create an operator form of FlattenAt :
Apply the operator to different expressions:
Properties & Relations (2)
History
Introduced in 1991 (2.0)
Text
Wolfram Research (1991), FlattenAt, Wolfram Language function, https://reference.wolfram.com/language/ref/FlattenAt.html.
CMS
Wolfram Language. 1991. "FlattenAt." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/FlattenAt.html.
APA
Wolfram Language. (1991). FlattenAt. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/FlattenAt.html
BibTeX
@misc{reference.wolfram_2025_flattenat, author="Wolfram Research", title="{FlattenAt}", year="1991", howpublished="\url{https://reference.wolfram.com/language/ref/FlattenAt.html}", note=[Accessed: 04-January-2026]}
BibLaTeX
@online{reference.wolfram_2025_flattenat, organization={Wolfram Research}, title={FlattenAt}, year={1991}, url={https://reference.wolfram.com/language/ref/FlattenAt.html}, note=[Accessed: 04-January-2026]}