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需要有關 For 循環的幫助

我是 JSL 的新手，但在這個社區的幫助下，我能夠編寫一段代碼來從 URL 收集特定污染物和時間段的空氣質量數據。 除了 URL 中沒有數據然後 For 循環中斷之外，代碼中的一切正常。 有沒有辦法設置條件，以便 For 循環忽略沒有數據的表？ 我正在粘貼下面的代碼。 如果您將 2021 年指定為 'end_year'，則代碼可以正常工作，但如果您將 2022 年指定為 'end_year'，則代碼會中斷，因為下半年還沒有數據（第 35 行）。

 

Names Default To Here(1);

//************************************INPUT****************************//

parameter= "SO2"; // 1. Pick from "NO2", "OZONE", "PM25HR", "NOX", "NO", "CO", "SO2"//
start_year= 2019; //   2. Specify start year
end_year= 2021; //     3. specify end year


//--------------------------------------------------------------------------------------------------------------

//This URL downloads data from Jan 1st until June 30
dl_url1= "https://www.arb.ca.gov/aqmis2/display.php?sitelist=All&filefmt=csv&fname=" || parameter || "_PICKDATA_^temp_year^-6-30&datafmt=dvde&download=y&first_date=^temp_year^-1-1&param=" || parameter || "&units=001&year=^temp_year^&county_name=--COUNTY--&basin=SC-South+Coast&latitude=--PART+OF+STATE--&report=PICKDATA&order=basin%2Ccounty_name%2Cs.name&submit=All+Sites&ptype=aqd&std15=&o3switch=new&hours=all&statistic=&qselect=Screened&start_mon=1&start_day=1&mon=6&day=30&rows=18";

tableList = {};

For(i = start_year, i <= end_year, i++,
 temp_year= Char(i);
 year_url = Eval Insert(dl_url1);
 
 dt_temp = Open(year_url, columns(
 New Column( "site", Character, "Nominal" ),
 New Column( "date",
   Numeric,
   "Continuous",
   Format( "yyyy-mm-dd", 10 ),
   Input Format( "yyyy-mm-dd" )
  )));
 dt_temp << delete rows( Index( N Rows(dt_temp) - 11, N Rows( dt_temp) ) ); //this code deletes the last 11 rows of data
 Insert Into( tableList, dt_temp << get name );
  );


//This URL downloads data from July 1st 1st until Dec 31
dl_url2= "https://www.arb.ca.gov/aqmis2/display.php?sitelist=All&filefmt=csv&fname=" || parameter || "_PICKDATA_^temp_year^-12-31&datafmt=dvde&download=y&first_date=^temp_year^-7-1&param=" || parameter || "&units=001&year=^temp_year^&county_name=--COUNTY--&basin=SC-South+Coast&latitude=--PART+OF+STATE--&report=PICKDATA&order=basin%2Ccounty_name%2Cs.name&submit=All+Sites&ptype=aqd&std15=&o3switch=new&hours=all&statistic=&qselect=Screened&start_mon=7&start_day=1&mon=12&day=31&rows=18";


For(i = start_year, i <= end_year, i++,
 temp_year= Char(i);
 year_url = Eval Insert(dl_url2);
 
 dt_temp = Open(year_url, columns(
 New Column( "site", Character, "Nominal" ),
 New Column( "date",
   Numeric,
   "Continuous",
   Format( "yyyy-mm-dd", 10 ),
   Input Format( "yyyy-mm-dd" )
  )));
 dt_temp << delete rows( Index( N Rows(dt_temp) - 11, N Rows( dt_temp) ) );
 Insert Into( tableList, dt_temp << get name );
  );
//The following code concat all tables
all_dt= new Table("All " || parameter || " Data");

For( i = 1, i <= N Items( tableList ), i++,
  Data Table(all_dt) << Concatenate(
  Data Table( tableList[i] ),
  append to first table(1)
 );
 Close( Data Table( tableList[i] ), No Save );
);

// Create Time (PST) Column
Data Table(all_dt) << New Column( "Column 4",
 Numeric,
 "Continuous",
 Format( "Best", 12 ),
 Set Selected
) << Move Selected Columns( {:Column 4}, after( :start_hour ) );

Data Table(all_dt):Column 4 << Input Format( "m/d/y h:m" ) <<
Set Name( "Time (PST)" ) << Format( "m/d/y h:m", 19 ) <<
Set Formula( :date + :start_hour * 3600 );

// Create Month Column
Data Table(all_dt) << New Column( "Month",
 Character,
 "Nominal",
 Formula( Substr( Format( :"Time (PST)"n, "Monddyyyy" ), 1, 3 ) )
) << Move Selected Columns( {:"Month"n}, after( :"Time (PST)"n ) );

// Create Year Column
Data Table(all_dt) << New Column( "Year",
 Character,
 "Nominal",
 Formula( Substr( Format( :"Time (PST)"n, "Monddyyyy" ), 6, 4 ) )
) << Move Selected Columns( {:"Year"n}, after( :"Month"n ) );

腳本編寫回复：需要有關 For 循環的幫助

您可以跳過具有 0 行數據的網址，如下所示：

 If(N Rows(dt_temp) > 0,
  dt_temp << delete rows(Index(N Rows(dt_temp) - 11, N Rows(dt_temp)));
  Insert Into(tableList, dt_temp << get name);
 ,
  Close(dt_temp, no save);
 );

如果你想在第一個沒有數據的表上停止（中斷）for 循環，你可以在 for 循環中使用 Break()：

 If(N Rows(dt_temp) == 0,
  Close(dt_temp, no save);
  break();
 );