Def snx (prefix: str, width: int):

..... "Returns the specified prefix+fixed-length self-increasing serial number"

....idx=0

....fmt = ' { } { {:0 & gt； {}}'. Format (prefix, width)

... and idx< 10 ** width:

..... output fmt.format(idx)

........idx = idx + 1

sn4 = snx(' 138 12 12 '，4)

Print (Next (sn4))? #? 138 12 120000

Print (Next (sn4))? #? 138 12 12000 1

If generality is not considered, only list expressions can be used:

phone _ numbers =[' 138 12 12 {:0 & gt； 4}'. Format of I in the range (10000)]

SQL, there is no iterator, and there is no such good string formatting, so it can only be a little troublesome:

declare @idx int = 0

while @ idx & lt 10000

begin

print(' 138 12 12 '+right(replicate(' 0 '，4) + convert(varchar(4)，@idx)，4))

select @idx = @idx + 1

end