Solving the challenge of Sum of Numbers following Hashes with Power Query
Power Query solution 1 for Sum of Numbers following Hashes, proposed by Kris Jaganah:
let
A = Excel.CurrentWorkbook(){[Name = "Table1"]}[Content],
B = Table.AddIndexColumn(A, "Id", 1),
C = Table.AddColumn(
B,
"Acc",
each List.Accumulate(List.FirstN(B[Data], [Id]), 0, (x, y) => if y = "#" then x + 1 else x)
),
D = Table.AddColumn(
C,
"Answer Expected",
each
let
a = List.Sum(Table.SelectRows(C, (x) => x[Data] <> "#" and x[Acc] = [Acc])[Data])
in
if [Data] = "#" then a else [Data]
)[[Answer Expected]]
in
DPower Query solution 2 for Sum of Numbers following Hashes, proposed by Aditya Kumar Darak 🇮🇳:
let
Source = Excel.CurrentWorkbook(){[Name = "data"]}[Content],
Group = Table.Group(
Source,
"Data",
{
"A",
each Table.ReplaceValue(_, "#", List.Sum(List.Skip([Data])), Replacer.ReplaceValue, {"Data"})
},
0,
(x, y) => Number.From(y = "#")
),
Return = Table.Combine(Group[A])
in
ReturnPower Query solution 3 for Sum of Numbers following Hashes, proposed by Alejandro Simón 🇵🇦 🇪🇸:
let
Source = Excel.CurrentWorkbook(){[Name = "Table1"]}[Content],
Sol = Table.Combine(
Table.Group(
Source,
"Data",
{
"A",
(x) =>
let
a = x[Data],
b = List.Skip(a),
c = Table.FromColumns({{List.Sum(b)} & b}, Table.ColumnNames(x))
in
c
},
0,
(x, y) => Number.From(y = "#")
)[A]
)
in
SolPower Query solution 4 for Sum of Numbers following Hashes, proposed by Luan Rodrigues:
let
Fonte = Tabela1,
grp = Table.Group(
Fonte,
"Data",
{
"grp",
each Table.TransformColumns(
_,
{"Data", (x) => if x = "#" then List.Sum(List.RemoveFirstN(_[Data])) else x}
)
},
0,
(a, b) => Number.From(b = "#")
)[grp],
res = Table.Combine(grp)
in
resPower Query solution 5 for Sum of Numbers following Hashes, proposed by Abdallah Ally:
let
Source = Excel.CurrentWorkbook(){[Name = "Table1"]}[Content],
AddInd = Table.AddIndexColumn(Source, "Index"),
AddCol = Table.AddColumn(
AddInd,
"My Answer",
each
if [Data] <> "#" then
[Data]
else
[
a = Table.SelectRows(AddInd, each [Data] = "#")[Index],
b = List.Transform(
a,
each {
_,
List.Sum(
List.Range(
AddInd[Data],
_ + 1,
(try a{List.PositionOf(a, _) + 1} otherwise Table.RowCount(Source)) - _ - 1
)
)
}
),
c = List.Select(b, (x) => x{0} = [Index]){0}{1}
][c]
)[[Data], [Answer Expected], [My Answer]],
Result = Table.AddColumn(AddCol, "Check", each [Answer Expected] = [My Answer])
in
ResultPower Query solution 6 for Sum of Numbers following Hashes, proposed by Ramiro Ayala Chávez:
let
S = Excel.CurrentWorkbook(){[Name = "Table1"]}[Content],
a = Table.AddColumn(S, "A", each if [Data] = "#" then 0 else 1),
b = Table.Group(a, {"A"}, {"G", each [Data]}, 0)[G],
c = List.Generate(
() => [i = 0],
each [i] < List.Count(b),
each [i = [i] + 1],
each if Number.IsEven([i]) then {List.Sum(b{[i] + 1})} else b{[i]}
),
Sol = Table.FromRows(List.Zip({S[Data], List.Combine(c)}), {"Data", "Answer Expected"})
in
SolPower Query solution 7 for Sum of Numbers following Hashes, proposed by CA Raghunath Gundi:
let
Source = Excel.CurrentWorkbook(){[Name = "Table1"]}[Content][[Data]],
Index = Table.AddIndexColumn(Source, "Index", 1, 1, Int64.Type),
Grp = Table.AddColumn(Index, "Grp", each if [Data] = "#" then [Index] else null),
FillDown = Table.FillDown(Grp, {"Grp"}),
#"No#" = Table.SelectRows(FillDown, each ([Data] <> "#")),
Grp2 = Table.Group(#"No#", {"Grp"}, {{"Sum", each List.Sum([Data]), type number}}),
Merge = Table.NestedJoin(FillDown, {"Grp"}, Grp2, {"Grp"}, "Grp2", JoinKind.LeftOuter),
ExpandedGrp2 = Table.ExpandTableColumn(Merge, "Grp2", {"Sum"}, {"Sum"})[[Data], [Sum]],
Result = Table.AddColumn(ExpandedGrp2, "Result", each if [Data] = "#" then [Sum] else [Data])[
[Result]
]
in
ResultPower Query solution 8 for Sum of Numbers following Hashes, proposed by Ahmed Ariem:
let
f = (x) =>
List.Combine(
Table.Group(
x,
"Data",
{"tmp", (x) => [a = List.Skip(x[Data]), b = {List.Sum(a)} & a][b]},
0,
(x, y) => Number.From(y = "#")
)[tmp]
),
Source = f(Excel.CurrentWorkbook(){[Name = "Table1"]}[Content])
in
SourcePower Query solution 9 for Sum of Numbers following Hashes, proposed by Alexandre Garcia:
let
A = Excel.CurrentWorkbook(){[Name = "Table1"]}[Content][Data],
B = Table.FromList(
List.Transform(
List.Zip({A, List.Positions(A)}),
each if _{0} = "#" then List.Sum(List.FirstN(List.Skip(A, _{1} + 1), each _ <> "#")) else _{0}
),
each {_},
{"Answer"}
)
in
BPower Query solution 10 for Sum of Numbers following Hashes, proposed by Krzysztof Kominiak:
let
Source = Table.FromRows(
Json.Document(
Binary.Decompress(
Binary.FromText(
"i45WUlaK1YlWMjYGUyYGYAoiZmoCpoyMICrMkKQMDZBVmEEoYxNkQagZxpgGmppDzAVSsQA=",
BinaryEncoding.Base64
),
Compression.Deflate
)
),
let
_t = ((type nullable text) meta [Serialized.Text = true])
in
type table [Data = _t]
),
GroupRows = Table.Group(
Source,
{"Data"},
{
{"NT", each _[Data]},
{
"Cr",
each {List.Sum(List.Transform(List.Skip(_[Data]), Number.From))}
& List.Transform(List.Skip(_[Data]), Number.From)
}
},
0,
(x, y) => Number.From(y[Data] = "#")
),
Result = Table.Combine(
Table.AddColumn(
GroupRows,
"All",
each Table.FromColumns({[NT], [Cr]}, {"Data", "Answer Expected"})
)[All]
)
in
ResultPower Query solution 11 for Sum of Numbers following Hashes, proposed by Francesco Bianchi 🇮🇹:
let
Source = Excel.CurrentWorkbook(){[Name = "Table1"]}[Content],
g =
let
a = List.Transform(Source[Data], each Number.From(_ = "#")),
b = List.Generate(
() => [RT = a{0}, i = 0],
each [i] < List.Count(a),
each [RT = [RT] + a{[i] + 1}, i = [i] + 1],
each [RT]
),
c = Table.FromRows(List.Zip({Source[Data], b}))
in
c,
s = List.Combine(
Table.Group(
g,
{"Column2"},
{{"Answer", each {List.Sum(List.Skip(_[Column1]))} & List.Skip(_[Column1])}}
)[#"Answer"]
)
in
sPower Query solution 12 for Sum of Numbers following Hashes, proposed by Tyler N.:
let
a = YourTable,
b = Table.AddIndexColumn(a, "i", 0, 1),
c = Table.AddColumn(
b,
"x",
each
let
d = [i],
e = {
[Data],
List.Sum(
List.Transform(
{
d + 1 .. try
Table.SelectRows(b, each [Data] = "#" and [i] > d)[i]{0} - 1
otherwise
List.Last(b[i])
},
each a[Data]{_}
)
)
}
in
e{Int8.From([Data] = "#")}
)
in
c[x]Power Query solution 13 for Sum of Numbers following Hashes, proposed by Joevan Bedico:
let
Source = Excel.CurrentWorkbook(){[Name = "Table5"]}[Content],
Answer = Table.FromColumns(
{
Source[Data],
List.Combine(
Table.Group(
Source,
"Data",
{
"A",
each
let
d = List.Skip([Data])
in
{List.Sum(d)} & d
},
0,
(x, y) => Number.From(y = "#")
)[A]
)
},
{"Data", "Answer Expected"}
)
in
AnswerSolving the challenge of Sum of Numbers following Hashes with Excel
Excel solution 1 for Sum of Numbers following Hashes, proposed by Bo Rydobon 🇹🇭:
=MAP(
A2:A20,
LAMBDA(
x,
IF(
x>"",
SUM(
TAKE(
x:A20,
XMATCH(
"#",
DROP(
VSTACK(
x:A20,
"#"
),
1
)
)
)
),
x
)
)
)Excel solution 2 for Sum of Numbers following Hashes, proposed by Bo Rydobon 🇹🇭:
=LET(z,A2:A20,s,SCAN(0,z>"",SUM),IF(z>"",LOOKUP(s,GROUPBY(s,z,SUM,0)),z))Excel solution 3 for Sum of Numbers following Hashes, proposed by Rick Rothstein:
=LET(
c,
A2:A20,
r,
ROWS(
c
),
s,
SEQUENCE(
r,
,
r,
-1
),
IF(
c="#",
INDEX(
SCAN(
0,
INDEX(
c,
s
),
LAMBDA(
a,
x,
IF(
x="#",
,
a+x
)
)
),
s-1
),
c
)
)Excel solution 4 for Sum of Numbers following Hashes, proposed by John V.:
=LET(
d,
A2:A20,
s,
SCAN(
0,
d>"",
SUM
),
IF(
d>"",
MAP(
s,
LAMBDA(
x,
SUM(
IF(
x=s,
d
)
)
)
),
d
)
)Excel solution 5 for Sum of Numbers following Hashes, proposed by 🇰🇷 Taeyong Shin:
=LET(
d,
A2:A20,
DROP(
GROUPBY(
HSTACK(
SCAN(
0,
d>"",
SUM
),
ROW(
d
)
),
d,
SUM,
1,
-2,
,
d<""
),
1,
2
)
)Excel solution 6 for Sum of Numbers following Hashes, proposed by Kris Jaganah:
=LET(a,A2:A20,b,SCAN(,N(a="#"),SUM),IF(a="#",MAP(b,LAMBDA(x,SUM(IF(a="#",0,a)*(b=x)))),a))Excel solution 7 for Sum of Numbers following Hashes, proposed by Julian Poeltl:
=LET(
D,
A2:A20,
S,
VSTACK(
D,
"#"
),
DROP(
IF(
S="#",
MAP(
SEQUENCE(
ROWS(
D
)
),
LAMBDA(
A,
SUM(
TAKE(
DROP(
S,
A
),
XMATCH(
"#",
DROP(
S,
A
)
)
)
)
)
),
S
),
-1
)
)Excel solution 8 for Sum of Numbers following Hashes, proposed by Aditya Kumar Darak 🇮🇳:
=LET(
_data, A2:A20,
_scan, SCAN(0, _data = "#", SUM),
_grp, GROUPBY(_scan, _data, SUM, 0, 0),
_rtrn, IF(_data <> "#", _data, VLOOKUP(_scan, _grp, 2)),
_rtrn
)Excel solution 9 for Sum of Numbers following Hashes, proposed by Timothée BLIOT:
=LET(A,A2:A20,DROP(GROUPBY(FILTER(HSTACK(SCAN(0,A,LAMBDA(w,v,IF(v="#",w+1,w))),SEQUENCE(ROWS(A))),A<>"#"),FILTER(A,A<>"#"),SUM,,-2),1,2))Excel solution 10 for Sum of Numbers following Hashes, proposed by Oscar Mendez Roca Farell:
=MAP(A2:A20,LAMBDA(a,IF(a>"",SUM(TAKE(a:A21,SUM(N(TAKE(TOCOL(IF(a:A21<"",e,ROW(a:A21)),2),2)*{-1;1})))),a)))Excel solution 11 for Sum of Numbers following Hashes, proposed by Duy Tùng:
=LET(a,A2:A20,b,SCAN(0,a>"",SUM),IF(a>"",LOOKUP(b,GROUPBY(b,a,SUM,0)),a))Excel solution 12 for Sum of Numbers following Hashes, proposed by Sunny Baggu:
=LET(
d,
A2:A20,
_a,
IF(
ISNUMBER(
--d
),
d,
"#" & SCAN(
0,
IF(
d = "#",
1,
0
),
LAMBDA(
a,
v,
a + v
)
)
),
_b,
CONCAT(
d & ","
),
_c,
BYROW(
--TEXTSPLIT(
_b,
",",
"#",
1,
,
0
),
LAMBDA(
a,
SUM(
a
)
)
),
_d,
"#" & SEQUENCE(
ROWS(
_c
)
),
IFNA(
XLOOKUP(
_a,
_d,
_c
),
_a
)
)Excel solution 13 for Sum of Numbers following Hashes, proposed by Sunny Baggu:
=LET(
_a,
SEQUENCE(
ROWS(
A2:A20
)
),
_b,
SORTBY(
IF(
ISNUMBER(
A2:A20
),
A2:A20,
0
),
_a,
-1
),
_c,
SCAN(
0,
_b,
LAMBDA(
a,
v,
IF(
v,
a + v,
v
)
)
),
_d,
FILTER(
_a,
_b = 0
),
_f,
XLOOKUP(
_d - 1,
_a,
_c
),
_g,
IFNA(
XLOOKUP(
_a,
_d,
_f
),
_b
),
SORTBY(
_g,
_a,
-1
)
)Excel solution 14 for Sum of Numbers following Hashes, proposed by LEONARD OCHEA 🇷🇴:
=LET(d,
A2:A20,
i,
SCAN(
,
N(
d=A2
),
SUM
),
n,
N(
+d
),
MAP(i,
n,
LAMBDA(a,
b,
IF(b,
b,
SUM((a=i)*n)))))Excel solution 15 for Sum of Numbers following Hashes, proposed by Anshu Bantra:
=LET(
arr_,
--TEXTSPLIT(
TEXTJOIN(
",",
,
A2:A20
),
",",
"#"
),
DROP(
TOCOL(
HSTACK(
BYROW(
arr_,
LAMBDA(
ro_,
SUM(
IFERROR(
ro_,
0
)
)
)
),
arr_
),
3
),
1
)
)Excel solution 16 for Sum of Numbers following Hashes, proposed by Md. Zohurul Islam:
=LET(
a,A2:A20,
b,SEQUENCE(COUNTA(a)),
d,MAP(b,a,LAMBDA(x,y,IF(y="#",x,0))),
e,SCAN(0,d,LAMBDA(x,y,MAX(x,y))),
f,GROUPBY(e,a,SUM,0,0),
g,XLOOKUP(b,TAKE(f,,1),TAKE(f,,-1),0),
h,MAP(a,g,LAMBDA(x,y,IF(x="#",y,x))),
h)Excel solution 17 for Sum of Numbers following Hashes, proposed by Pieter de B.:
=MAP(
A2:A20,
LAMBDA(
a,
LET(
b,
INDEX(
A2:A20,
ROW(
a
)+1
),
IF(
a="#",
SUM(
a:XLOOKUP(
"#",
b:A20,
b:A20,
A20
)
),
a
)
)
)
)Excel solution 18 for Sum of Numbers following Hashes, proposed by Hamidi Hamid:
=LET(
f,
A2:A20,
m,
ROWS(
f
),
mm,
SEQUENCE(
m,
,
m,
-1
),
y,
SORTBY(
f,
mm,
1
),
d,
IFERROR(
y*1,
0
),
x,
SORTBY(
SCAN(
0,
d,
LAMBDA(
a,
b,
IF(
b=0,
-b,
b+a
)
)
),
mm
),
IF(
f="#",
VSTACK(
DROP(
x,
1
),
0
),
f
)
)Excel solution 19 for Sum of Numbers following Hashes, proposed by Asheesh Pahwa:
=LET(
d,
A2:A20,
xm,
XMATCH(
d,
"#"
),
s,
SEQUENCE(
ROWS(
xm
)
),
I,
IF(
ISNUMBER(
xm
),
s,
0
),
sc,
SCAN(
0,
I,
LAMBDA(
x,
y,
IF(
y,
y,
x
)
)
),
u,
UNIQUE(
sc
),
REDUCE(
A1,
u,
LAMBDA(
a,
v,
VSTACK(
a,
LET(
f,
FILTER(
d,
sc=v
),
d,
DROP(
f,
1
),
VSTACK(
SUM(
d
),
d
)
)
)
)
)
)Excel solution 20 for Sum of Numbers following Hashes, proposed by ferhat CK:
=LET(w,SCAN(,IF(A2:A20="#",1,0),SUM),DROP(REDUCE(0,UNIQUE(w),LAMBDA(x,y,VSTACK(x,LET(a,DROP(FILTER(A2:A20,w=y),1),VSTACK(SUM(a),a))))),1))Excel solution 21 for Sum of Numbers following Hashes, proposed by Ankur Sharma:
=LET(r, A2:A20,
MAP(r, SEQUENCE(COUNTA(r)), LAMBDA(y, z,
LET(tr, DROP(VSTACK(r, "#"), z),
IF(y="#", SUM(TAKE(tr, XMATCH("#", tr))), y)))))Excel solution 22 for Sum of Numbers following Hashes, proposed by Bilal Mahmoud kh.:
="#",
SUM(
OFFSET(
x:A20,
1,
0,
IFNA(
MATCH(
"#",
DROP(
x:A20,
1
),
0
)-1,
COUNTA(
x:A20
)
),
1
)
),
x)))Excel solution 23 for Sum of Numbers following Hashes, proposed by Imam Hambali:
=LET(
d,
A2:A20,
sc,
SCAN(
,
IF(
d="#",
1,
0
),
SUM
),
sb,
SUBSTITUTE(
d,
"#",
0
)*1,
gb,
GROUPBY(
sc,
sb,
SUM,
0,
0
),
IF(
sb=0,
XLOOKUP(
sc,
TAKE(
gb,
,
1
),
TAKE(
gb,
,
-1
)
),
sb
)
)Excel solution 24 for Sum of Numbers following Hashes, proposed by Julien Lacaze:
=LET(d,
A2:A20,
m,
MAP(
d,
LAMBDA(
a,
XMATCH(
TRUE,
A2:a="#",
,
-1
)
)
),
s,
--SUBSTITUTE(
d,
"#",
0
),
MAP(m,
d,
s,
LAMBDA(a,
b,
c,
IF(c,
b,
SUM(s*--(m=a))))))Excel solution 25 for Sum of Numbers following Hashes, proposed by Andres Rojas Moncada:
=LET(nn,
IFERROR(
A2:A20/1,
0
),
ii,
SCAN(
0,
nn=0,
SUM
),
MAP(nn,
ii,
LAMBDA(n,
i,
IF(n,
n,
SUM((ii=i)*nn)))))Excel solution 26 for Sum of Numbers following Hashes, proposed by Gabriel Pugliese:
=LET(z;
A2:A20;
z_;
LAMBDA(
x;
INDEX(
x;
SEQUENCE(
COUNTA(
x
);
1;
COUNTA(
x
);
-1
);
1
)
);
q;
z_(z);
sc;
SCAN(
0;
q;
LAMBDA(
a;
v;
IF(
ISNUMBER(
v
);
a+v;
0
)
)
);
w;
DROP(z_(sc);
1);
HSTACK(
z;
IF(
z="#";
w;
z
)
))Excel solution 27 for Sum of Numbers following Hashes, proposed by Tomasz Jakóbczyk:
=IFNA(
IF(
A2="#",
SUM(
OFFSET(
A2,
,
,
MATCH(
"#",
A3:$A$20,
0
)
)
),
A2
),
SUM(
OFFSET(
$A$1,
CELL(
"row",
XLOOKUP(
"#",
$A$2:$A$20,
$A$2:$A$20,
"",
0,
-1
)
),
,
ROWS(
$A$1:$A$20
)-CELL(
"row",
XLOOKUP(
"#",
$A$2:$A$20,
$A$2:$A$20,
"",
0,
-1
)
)
)
)
)Excel solution 28 for Sum of Numbers following Hashes, proposed by Gupta Harsh:
=IF(
A2="#",
SUM(
OFFSET(
A2,
,
,
IFNA(
MATCH(
"#",
A3:$A$20,
0
),
COUNT(
A3:$A$20
)+1
)
)
),
A2
)
2nd Solution:-
=IF(
A2<>"#",
A2,
SUM(
A2:INDEX(
A3:$A$20,
IFERROR(
MATCH(
"#",
A3:$A$20,
0
),
COUNT(
A3:$A$20
)
)
)
)
)Excel solution 29 for Sum of Numbers following Hashes, proposed by Christian Mbolanantenaina:
=LET(
in,A2:A20,
Join,";"&TEXTJOIN(";",,in)&";",
Sm,BYROW(--IFERROR(TEXTSPLIT(Join,";","#",1),0),SUM),
Tb,--TEXTSPLIT(Join,";","#",1),
Tab,HSTACK(Sm,Tb),
out,TOCOL(Tab,3),
out)Solving the challenge of Sum of Numbers following Hashes with Python
Python solution 1 for Sum of Numbers following Hashes, proposed by Konrad Gryczan, PhD:
import pandas as pd
path = "591 Sum of Numbers following Hashes.xlsx"
input = pd.read_excel(path, usecols="A", nrows=20)
test = pd.read_excel(path, usecols="B", nrows=20)
input['group'] = (input['Data'] == '#').cumsum()
input['Data'] = pd.to_numeric(input['Data'], errors='coerce')
input['Data'] = input['Data'].fillna(input.groupby('group')['Data'].transform('sum')).astype('int64')
print(input['Data'].equals(test['Answer Expected'])) # True
Python solution 2 for Sum of Numbers following Hashes, proposed by Luan Rodrigues:
PY Solution!
import pandas as pd
file = 'Excel_Challenge_591 - Sum of Numbers following Hashes.xlsx'
df = pd.read_excel(file,usecols="A")
df['grp'] = df.index.to_series().where(df['Data'] == '#').ffill()
grp = df[df['Data'] != '#'].groupby('grp').sum()
merge = pd.merge(df, grp,left_on='grp',right_index=True, how='inner')[['Data_x','Data_y']]
merge['rst'] = merge['Data_x'].where(merge['Data_x'] != '#',merge['Data_y'])
print(merge[['rst']])
Solving the challenge of Sum of Numbers following Hashes with Python in Excel
Python in Excel solution 1 for Sum of Numbers following Hashes, proposed by Alejandro Campos:
df = xl("A1:A20", headers=True)
df_inverted = df.iloc[::-1].reset_index(drop=True)
answers = []
cumulated_sum = 0
for value in df_inverted['Data']:
if value == '#':
answers.append(cumulated_sum)
cumulated_sum = 0
else:
cumulated_sum += value
answers.append(value)
df_inverted['Answer Expected'] = answers
df_final = df_inverted.iloc[::-1].reset_index(drop=True)
df_final
Python in Excel solution 2 for Sum of Numbers following Hashes, proposed by Anshu Bantra:
data = list(xl("A1:A20", headers=True).values)
for i in range(len(data)):
sum_below = 0
if data[i] == "#":
for x in data[i+1:]:
if x == "#":
break
else:
sum_below += x
data[i] = sum_below
data
Python in Excel solution 3 for Sum of Numbers following Hashes, proposed by Anshu Bantra:
lst = list(xl("A1:A20", headers=True).values)
idxs = [idx for idx, num in enumerate(lst) if num=='#']
for idx in range(len(idxs)):
if idx == len(idxs)-1:
lst[idxs[idx]] = sum(lst[idxs[idx]+1:len(lst)])
else:
lst[idxs[idx]] = sum(lst[idxs[idx]+1:idxs[idx+1]])
lst
Solving the challenge of Sum of Numbers following Hashes with R
R solution 1 for Sum of Numbers following Hashes, proposed by Konrad Gryczan, PhD:
library(tidyverse)
library(readxl)
path = "Excel/591 Sum of Numbers following Hashes.xlsx"
input = read_excel(path, range = "A1:A20")
test = read_excel(path, range = "B1:B20")
result = input %>%
mutate(group = cumsum(Data == "#")) %>%
mutate(`Answer Expected` = ifelse(Data == "#",
sum(as.numeric(Data), na.rm = TRUE),
as.numeric(Data)), .by = group)
all.equal(result$`Answer Expected`, test$`Answer Expected`)
#> [1] TRUE
&&