digitalmars.D.learn - Storing struct in a array

Vino (19/19) Jan 09 2018 Hi All,

Vino (32/51) Jan 09 2018 Hi All,
thedeemon (10/13) Jan 09 2018 Sure, you can just pass the type of your struct to csvReader:

Vino (20/34) Jan 09 2018 Hi Deemon,

Vino (22/60) Jan 09 2018 Details

thedeemon (28/35) Jan 09 2018 First you write a template function that takes an array of some

Vino (34/69) Jan 10 2018 Hi Deemon,

Vino <vino.bheeman hotmail.com> writes:

Hi All,

  It is possible to store struct in a array ans use the same in 
csvReader e.g.

import std.stdio;
import std.container.array;

void main () {
Array!string a;
struct Layout { string name; int value; double other; }

a.insert(Layout);
auto record =  
uFile.byLineCopy().joiner("\n").csvReader!(Tuple!a[0]))
foreach (record; records)
{
     writeln(record.name);
     writeln(record.value);
     writeln(record.other);
}

From,
Vino.B

Jan 09 2018

Vino <vino.bheeman hotmail.com> writes:

On Tuesday, 9 January 2018 at 13:49:41 UTC, Vino wrote:
 Hi All,

  It is possible to store struct in a array ans use the same in 
 csvReader e.g.

 import std.stdio;
 import std.container.array;

 void main () {
 Array!string a;
 struct Layout { string name; int value; double other; }

 a.insert(Layout);
 auto record =  
 uFile.byLineCopy().joiner("\n").csvReader!(Tuple!a[0]))
 foreach (record; records)
 {
     writeln(record.name);
     writeln(record.value);
     writeln(record.other);
 }

 From,
 Vino.B

Hi All,

  Was able to find on hot to store a struct in an array, but not 
able to use that array in csvReader

Program:
import std.algorithm: joiner;
import std.container.array;
import std.csv: csvReader;
import std.stdio: File, writeln;
import std.typecons: Tuple, tuple;

void main () {
auto fName = 
"C:\\Users\\bheev1\\Desktop\\Current\\Script\\Others\\Table1.csv";
auto uFile = File(fName, "r");
struct T1 { string Name; string Country; int Age; }
Array!T1 T1s;
foreach (record; 
uFile.byLineCopy().joiner("\n").csvReader!(Tuple!T1s))
writeln(record);
}

Error:
C:\D\dmd2\windows\bin\..\..\src\phobos\std\typecons.d(523): 
Error: template instance parseSpecs!(T1s) cannot use local 'T1s' 
as parameter to non-global template
  parseSpecs(Specs...)
C:\D\dmd2\windows\bin\..\..\src\phobos\std\typecons.d(635): 
Error: CTFE failed because of previous errors in injectNamedFields
ArrayStruct.d(12): Error: template instance 
ArrayStruct.main.Tuple!(T1s) error instantiating
Failed: ["dmd", "-v", "-o-", "ArrayStruct.d", "-I."]

From,
Vino.B

Jan 09 2018

thedeemon <dlang thedeemon.com> writes:

On Tuesday, 9 January 2018 at 13:49:41 UTC, Vino wrote:
 Hi All,

  It is possible to store struct in a array ans use the same in 
 csvReader

Sure, you can just pass the type of your struct to csvReader:

struct Layout { string name; int value; double other; }

auto readArrayOfStructs(string fname) {
     Array!Layout res;
     foreach(record; fname.readText.csvReader!Layout('\t')) {
         res ~= record;
     }
     return res;
}

Jan 09 2018

Vino <vino.bheeman hotmail.com> writes:

On Tuesday, 9 January 2018 at 17:00:05 UTC, thedeemon wrote:
 On Tuesday, 9 January 2018 at 13:49:41 UTC, Vino wrote:
 Hi All,

  It is possible to store struct in a array ans use the same in 
 csvReader

 Sure, you can just pass the type of your struct to csvReader:

 struct Layout { string name; int value; double other; }

 auto readArrayOfStructs(string fname) {
     Array!Layout res;
     foreach(record; fname.readText.csvReader!Layout('\t')) {
         res ~= record;
     }
     return res;
 }

Hi Deemon,

   Thank you, and sorry for the confusion, the requirement is as 
below

auto reader(T) (Array!T T1s, T fname) {
auto uFile = File(fName, "r");
foreach (record; 
uFile.byLineCopy().joiner("\n").csvReader!(Tuple!T1s)) // receive 
the type and fetch the record
writeln(record);
}

void main () {
auto fName = 
"C:\\Users\\bheev1\\Desktop\\Current\\Script\\Others\\Table1.csv";
struct T1 { string Name; string Country; int Age; }
Array!T1 T1s;
reader(fName, T1s); // pass the array Type as a function parameter
}


From,
Vino.B

Jan 09 2018

Vino <vino.bheeman hotmail.com> writes:

On Tuesday, 9 January 2018 at 17:41:10 UTC, Vino wrote:
 On Tuesday, 9 January 2018 at 17:00:05 UTC, thedeemon wrote:
 On Tuesday, 9 January 2018 at 13:49:41 UTC, Vino wrote:
 Hi All,

  It is possible to store struct in a array ans use the same 
 in csvReader

 Sure, you can just pass the type of your struct to csvReader:

 struct Layout { string name; int value; double other; }

 auto readArrayOfStructs(string fname) {
     Array!Layout res;
     foreach(record; fname.readText.csvReader!Layout('\t')) {
         res ~= record;
     }
     return res;
 }

 Hi Deemon,

   Thank you, and sorry for the confusion, the requirement is as 
 below

 auto reader(T) (Array!T T1s, T fname) {
 auto uFile = File(fName, "r");
 foreach (record; 
 uFile.byLineCopy().joiner("\n").csvReader!(Tuple!T1s)) // 
 receive the type and fetch the record
 writeln(record);
 }

 void main () {
 auto fName = 
 "C:\\Users\\bheev1\\Desktop\\Current\\Script\\Others\\Table1.csv";
 struct T1 { string Name; string Country; int Age; }
 Array!T1 T1s;
 reader(fName, T1s); // pass the array Type as a function 
 parameter
 }


 From,
 Vino.B

Details

For example let say we have 3 struct
auto read(T) (T Filename, T ArrayType) {
T ArrayType res;
foreach (record; 
Filename.byLineCopy().joiner("\n").csvReader!(T)(Tuple!ArrayType))
foreach(i, T; ColumnTypes) { res[i].insert(record[i]); }
	}
	return res;
}

void main () {

struct S1 { }
struct S2 { }
struct S3 { }

Get user input(UI)
if(UI == S1) {
Array!S1 T1;
writeln(read(File1, Array Type));
}

From,
Vino.B

Jan 09 2018

thedeemon <dlang thedeemon.com> writes:

On Tuesday, 9 January 2018 at 18:09:58 UTC, Vino wrote:
  It is possible to store struct in a array ans use the same 
 in csvReader

 Sure, you can just pass the type of your struct to csvReader:



 Array!T1 T1s;
 reader(fName, T1s); // pass the array Type as a function 
 parameter


First you write a template function that takes an array of some 
generic type and fills it with records from CSV file:

void readData(DataType)(string fname, ref Array!DataType arr) {
     foreach (record; fname.readText.csvReader!DataType('\t')) {
         arr ~= record;
     }
}

Then you can use it in your main program with different types:

struct S1 { string name; string value; int other; }
struct S2 { int a; string b; }

void main () {
     ...
     if (someCondition) {
         Array!S1 arr1;
         readData("data1.csv", arr1);
     } else {
         Array!S2 arr2;
         readData("data2.csv", arr2);
     }
}

A little advice. Kindly pause and spend an evening reading this 
book:
http://ddili.org/ders/d.en/

Currently your code pieces look like a soup produced by someone 
who still confuses variables and types, and lacks basic 
programming skills. Read the book, don't rush with writing broken 
code.

Jan 09 2018

Vino <vino.bheeman hotmail.com> writes:

On Tuesday, 9 January 2018 at 19:05:48 UTC, thedeemon wrote:
 On Tuesday, 9 January 2018 at 18:09:58 UTC, Vino wrote:
  It is possible to store struct in a array ans use the same 
 in csvReader

 Sure, you can just pass the type of your struct to csvReader:



 Array!T1 T1s;
 reader(fName, T1s); // pass the array Type as a function 
 parameter


 First you write a template function that takes an array of some 
 generic type and fills it with records from CSV file:

 void readData(DataType)(string fname, ref Array!DataType arr) {
     foreach (record; fname.readText.csvReader!DataType('\t')) {
         arr ~= record;
     }
 }

 Then you can use it in your main program with different types:

 struct S1 { string name; string value; int other; }
 struct S2 { int a; string b; }

 void main () {
     ...
     if (someCondition) {
         Array!S1 arr1;
         readData("data1.csv", arr1);
     } else {
         Array!S2 arr2;
         readData("data2.csv", arr2);
     }
 }

 A little advice. Kindly pause and spend an evening reading this 
 book:
 http://ddili.org/ders/d.en/

 Currently your code pieces look like a soup produced by someone 
 who still confuses variables and types, and lacks basic 
 programming skills. Read the book, don't rush with writing 
 broken code.

Hi Deemon,

  I agree that my code is broken code and I am a Newbie in the 
world of programming, the confusion begin when i started writing 
the second module, and now i was able to find the issue, and the 
real requirement. The requirement is as below.

Program: The below program works.
auto reader(MyStruct) (File fname, auto ref MyStruct st) {
alias ColumnTypes = AliasSeq!(MyStruct);
foreach (record; 
fname.byLineCopy().joiner("\n").csvReader!(Tuple!ColumnTypes)(null)) {
writeln(record[0], record[1], record[2]);
}

void main () {
auto fname = 
File("C:\\Users\\bheev1\\Desktop\\Current\\Script\\Others\\Table2.csv");
auto Table = baseName(stripExtension(fname));
struct S1 { string Name; string Country; int Age; }
S1 Table1s;
reader(File(fname), join([Table, "1s"]));
}

The requirement is as below
The function reader should store the data in column wise Array 
and return the same.

Array!<Type has to be taken from ColumnTypes < Name of the array 
has to be taken from the header data as the CSV file has header 
Name, Country, Age using records.header)
e.g
Array!string Name; (records.header[0]);
Array!string Country;(records.header[1]);
Array!string Age;(records.header[2]);

and return the above arrays

From,
Vino.B

Jan 10 2018

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