Select rows with a specific element from a given table

Question

Lets say I have 4 rows in

alist = {{1, 1, 3, 3, 1, 6}, {1, 1, 3, 4, 1, 1, x}, {1, 2, 3, 3, 1, 
    6}, {1, 2, 3, 4, 1, 1, x}};

If I want to select and print out only the rows with the "x" from the previous one, i.e.,

{{1, 1, 3, 4, 1, 1, x}, {1, 2, 3, 4, 1, 1, x}}

Is there a way to do it?

Answer 1

Using Select:

Select[alist, MemberQ[#, x] &]

Using Pick:

Pick[alist, MemberQ[#, x] & /@ alist]

Using Cases:

Cases[alist, {p___, x, q___}]

Using ContainsAny

Pick[alist, ContainsAny[#, {x}] & /@ alist]

or

Select[ContainsAny[{x}]][alist]

---

Result:

{{1, 1, 3, 4, 1, 1, x}, {1, 2, 3, 4, 1, 1, x}}

Answer 2

Select[alist,EqualTo[x]@*Last]

Answer 3

list = 
  {{1, 1, 3, 3, 1, 6}, 
   {1, 1, 3, 4, 1, 1, x},
   {1, 2, 3, 3, 1, 6}, 
   {1, 2, 3, 4, 1, 1, x}};

Using ReplaceAll

list /. {__?NumberQ} :> Nothing

{{1, 1, 3, 4, 1, 1, x}, {1, 2, 3, 4, 1, 1, x}}

Using SequenceSplit (new in 11.3)

Catenate @ SequenceSplit[list, {{__, _?NumberQ}}]

{{1, 1, 3, 4, 1, 1, x}, {1, 2, 3, 4, 1, 1, x}}

Answer 4

 list = 
  {{1, 1, 3, 3, 1, 6}, 
   {1, 1, 3, 4, 1, 1, x},
   {1, 2, 3, 3, 1, 6}, 
   {1, 2, 3, 4, 1, 1, x}};

---

Using DeleteCases:

DeleteCases[list, {__?NumericQ}]

{{1, 1, 3, 4, 1, 1, x}, {1, 2, 3, 4, 1, 1, x}}

Or using Replace at level 1:

Replace[list, {a__?NumericQ} :> Nothing, {1}]

{{1, 1, 3, 4, 1, 1, x}, {1, 2, 3, 4, 1, 1, x}}

Or using ReplaceList:

ReplaceList[list, {___, s : {p___, x, q___}, ___} :> s]

{{1, 1, 3, 4, 1, 1, x}, {1, 2, 3, 4, 1, 1, x}}