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digitalmars.D.learn - Why map return [] ?

reply Suliman <evermind live.ru> writes:
auto x = MySQLTablesRange.map!(a=>a);
writeln(x);

return: []

while next code:
MySQLTablesRange.each!(a=>a.writeln);

return data line by line.

Why?
Apr 14
parent reply cym13 <cpicard openmailbox.org> writes:
On Friday, 14 April 2017 at 15:29:33 UTC, Suliman wrote:
 auto x = MySQLTablesRange.map!(a=>a);
 writeln(x);

 return: []

 while next code:
 MySQLTablesRange.each!(a=>a.writeln);

 return data line by line.

 Why?
What library is that supposed to be?
Apr 14
parent reply Suliman <evermind live.ru> writes:
On Friday, 14 April 2017 at 15:35:15 UTC, cym13 wrote:
 On Friday, 14 April 2017 at 15:29:33 UTC, Suliman wrote:
 auto x = MySQLTablesRange.map!(a=>a);
 writeln(x);

 return: []

 while next code:
 MySQLTablesRange.each!(a=>a.writeln);

 return data line by line.

 Why?
What library is that supposed to be?
http://code.dlang.org/packages/mysql-native
Apr 14
parent reply Suliman <evermind live.ru> writes:
On Friday, 14 April 2017 at 15:38:19 UTC, Suliman wrote:
 On Friday, 14 April 2017 at 15:35:15 UTC, cym13 wrote:
 On Friday, 14 April 2017 at 15:29:33 UTC, Suliman wrote:
 auto x = MySQLTablesRange.map!(a=>a);
 writeln(x);

 return: []

 while next code:
 MySQLTablesRange.each!(a=>a.writeln);

 return data line by line.

 Why?
What library is that supposed to be?
http://code.dlang.org/packages/mysql-native
I found problem! ResultRange should be converted to array before it can be `map`ed
Apr 14
parent reply Rene Zwanenburg <renezwanenburg gmail.com> writes:
On Friday, 14 April 2017 at 15:49:00 UTC, Suliman wrote:
 I found problem! ResultRange should be converted to array 
 before it can be `map`ed
That shouldn't be necessary. Can you post your complete code?
Apr 14
parent Suliman <evermind live.ru> writes:
On Friday, 14 April 2017 at 15:55:13 UTC, Rene Zwanenburg wrote:
 On Friday, 14 April 2017 at 15:49:00 UTC, Suliman wrote:
 I found problem! ResultRange should be converted to array 
 before it can be `map`ed
That shouldn't be necessary. Can you post your complete code?
ResultRange MySQLTablesRange = mysqlconnection.query(`SELECT table_name FROM information_schema.tables;`); auto x = MySQLTablesRange.map!(a=>a[0].coerce!string.split("_")[1]); writeln(x); output: [] while: MySQLTablesRange.array.map!... output result
Apr 14