# Problem with array definition **URL:** \ **Category:** Help\ **Created:** [May 6, 2021, 5:57pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163 "2021-05-06T17:57:55Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![CConde](https://avatars.discourse-cdn.com/v4/letter/c/d6d6ee/32.png) [@CConde](https://fortran-lang.discourse.group/u/CConde)\ **Post date:** [May 6, 2021, 5:57pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/1 "2021-05-06T17:57:55Z")
Dear friends, Please, I would like to request your help with the following problem: I have to define a large array containing zeros which don’t fit in a single row due to I’m exceeding the maximun numbers of character per row. For example: a = [0, 0, 0, 0, 0, 0, …, 0, & 0, 0, 0, 0, … 0, 0] However, the second row cannot start with a zero given that, when compiling, I get this error " Syntax error in array constructor at (1). Zero is not a valid statement label at (1)" How can I overcome this problem? Many thanks for the help. ---
**Author:** ![ivanpribec](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/ivanpribec/32/3290_2.png) [@ivanpribec](https://fortran-lang.discourse.group/u/ivanpribec)\ **Post date:** [May 6, 2021, 6:11pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/2 "2021-05-06T18:11:14Z")
How about: ```auto integer, parameter :: n = 1000000 real :: a(n) a = 0 ``` ---
**Author:** ![vmagnin](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/vmagnin/32/28_2.png) [@vmagnin](https://fortran-lang.discourse.group/u/vmagnin)\ **Post date:** [May 6, 2021, 6:50pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/3 "2021-05-06T18:50:37Z")
> [@CConde](#): > > a = [0, 0, 0, 0, 0, 0, …, 0, & > 0, 0, 0, 0, … 0, 0] Although @ivanpribec solution is THE solution, note that the label problem could probably be avoided by putting an & at the start of the second line: ```fortran a = [0, 0, 0, 0, 0, 0, …, 0, & & 0, 0, 0, 0, … 0, 0] ``` **Updated:** in fact, no. See the post by @themos downward: [Problem with array definition - #9 by themos](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/9) In free-form format, there is no error and no need to add an &. And in fixed-form, the trailing & is not accepted. ---
**Author:** ![rwmsu](https://avatars.discourse-cdn.com/v4/letter/r/48db29/32.png) [@rwmsu](https://fortran-lang.discourse.group/u/rwmsu)\ **Post date:** [May 6, 2021, 6:57pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/4 "2021-05-06T18:57:11Z")
and if a is allocatable you can do allocate(a(n), source=0) ---
**Author:** ![CConde](https://avatars.discourse-cdn.com/v4/letter/c/d6d6ee/32.png) [@CConde](https://fortran-lang.discourse.group/u/CConde)\ **Post date:** [May 6, 2021, 7:10pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/5 "2021-05-06T19:10:44Z")
@ivanpribec, @vmagnin, @rwmsu, many thanks for your help. ---
**Author:** ![johnalx](https://avatars.discourse-cdn.com/v4/letter/j/b38774/32.png) [@johnalx](https://fortran-lang.discourse.group/u/johnalx)\ **Post date:** [May 6, 2021, 8:12pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/6 "2021-05-06T20:12:34Z")
How about using a `data` statement ``` integer, parameter :: n = 20 real, dimension(n) :: a; data a/n*0.0/ print *,a ``` produces 20 values of `0.0` If this is fixed format file, then you need to add a continuation character in column 6 ``` ! |<-- column 7 a = [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, &0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0] ``` ---
**Author:** ![nbehrnd](https://avatars.discourse-cdn.com/v4/letter/n/e0b2c6/32.png) [@nbehrnd](https://fortran-lang.discourse.group/u/nbehrnd)\ **Post date:** [May 6, 2021, 9:25pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/7 "2021-05-06T21:25:27Z")
By the large number of 0-elements in the examples above, on one hand, and some prior exposure to Python’s [scripy](https://docs.scipy.org/doc/scipy/reference/index.html) library on the other I noticed Fortran seems equally to work with [_sparse matrices_](https://docs.scipy.org/doc/scipy/reference/sparse.html#example-1) (or, perhaps more suitable for the parlance of Fortran, a _sparse arrays_). One of the entries found is [this one](https://stackoverflow.com/questions/16493753/automated-sparse-matricies-in-fortran). ---
**Author:** ![FortranFan](https://avatars.discourse-cdn.com/v4/letter/f/96bed5/32.png) [@FortranFan](https://fortran-lang.discourse.group/u/FortranFan)\ **Post date:** [May 6, 2021, 10:22pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/8 "2021-05-06T22:22:28Z")
> [@johnalx](#): > > How about using a `data` statement … @johnalx , Welcome to the forum. Re: the “data statement,” note the use of `DATA` also imparts the `SAVE` attribute to the variable, essentially making it a static variable and adversely impacting thread-safety. Coders may not want that attribute in modern applications. An option to consider if `implied-do` is of interest is ```Fortran a = [( xx, integer :: i = 1, n )] !<-- xx can be a constant such as zero, or a valid expression involving `i` ``` ```auto ``` ---
**Author:** ![themos](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/themos/32/521_2.png) [@themos](https://fortran-lang.discourse.group/u/themos)\ **Post date:** [May 7, 2021, 10:18am UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/9 "2021-05-07T10:18:25Z")
Hello, I am guessing you are using the gfortran compiler and you wrote something like this and saved it in a file foo.f. ``` c234567 dimension a(6) a=[0,0,0, & 0 ,0,0] end ``` What went wrong here is that you used free-format Fortran but the conventions of gfortran treat the contents of foo.f as fixed-form Fortran. In fixed-form the trailing ampersand (&) is an error (which is the _Error: Syntax error in array constructor at (1)_) and that first zero on line 3 is interpreted as a statement label and not part of a statement (which is the _Zero is not a valid statement label at (1)_) If you write free-format Fortran you must either put it in a file with a filename extension that the compiler expects (most compilers will accept .f90 for this) or override the compiler’s defaults with a command line option (in gfortran’s case, _-ffree-form_) ---
**Author:** ![johnalx](https://avatars.discourse-cdn.com/v4/letter/j/b38774/32.png) [@johnalx](https://fortran-lang.discourse.group/u/johnalx)\ **Post date:** [May 7, 2021, 12:41pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/10 "2021-05-07T12:41:23Z")
I did not know that about the `data` statement. Thank you this caveat. ---
**Author:** ![ivanpribec](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/ivanpribec/32/3290_2.png) [@ivanpribec](https://fortran-lang.discourse.group/u/ivanpribec)\ **Post date:** [May 7, 2021, 1:31pm UTC](https://fortran-lang.discourse.group/t/problem-with-array-definition/1163/11 "2021-05-07T13:31:24Z")
It is also possible to initialize the array with a constant: ```auto module mymod implicit none integer, parameter :: n = 20 real :: a(n) = 0 ! implicit save end module program main use mymod print *, a end program ``` Edit: for any new Fortran programmers, the following might be more illustrating of what implicit save means ```nohighlight module mymod implicit none real :: a(5) = 0 ! implicit save end module module usemymod use mymod, only: a implicit none private public :: modify_a contains subroutine modify_a() a(1) = 42. end subroutine end module program main use usemymod, only: modify_a call modify_a block use mymod, only: a print *, a ! a(1) equals 42. end block end program ```