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Continuous Append CSV File

  • #1
  • First Post: Sep 18, 2009 3:09pm Sep 18, 2009 3:09pm
Hey Guys,

I have a need to wirtie an EA (?) which performs the following:

1. Can export OHLC data amd Indicator data to CSV file.
2. If the file already exists, then the file should be appended to.
3. Naturally if the file does not exist then the file needs to be created (eg with 1000 rows of data).

My intention is essentially IPC as I have a separate analysis program that can read in the file and work its magic.

Can anyone point me in the right direction by way of examples ? I think the biggest question mark in my mind is the determining if the file exists (Win API ?) and the append to the end of a file thing (MT4 only support FILE WRITE and FILE READ ?).

All help muchly appreciated !!

TheGeneral
  • #2
  • Sep 18, 2009 8:58pm Sep 18, 2009 8:58pm
You don't need the API for this.
Look at help on the File commands.
There might be one to see if a file exists, don't remember, but if not just open it for Read only and if it returns a handle it exists.
Use SEEK to append.
handle = FileOpen(sFileName, FILE_READ|FILE_WRITE|FILE_CSV, ";");
bRtn = FileSeek(handle, 0, SEEK_END);
  • #3
  • Sep 18, 2009 9:30pm Sep 18, 2009 9:30pm
i used cvs files to make a trade copy ea, i can send, edit settings with cvs files, i can do bout anything with cvs files, i like teaching more than doing, il help you along if your up for it

i was able to fully teach my self using the help in editor

your question, to see if the file exists

heres pasted from help

int handle;
string str;
handle=FileOpen("filename.csv", FILE_CSV|FILE_READ);
if(handle>0)
{
str=FileReadString(handle);
FileClose(handle);
}

if handle is above 0, yes it exists

also see the extension csv
thats a error, so look for that when copy n pasting from the help data

but the error here FILE_CSV
must stay, as its a error the mt4 creators never fixed

the line should be like this
handle=FileOpen("filename.cvs", FILE_CSV|FILE_READ);

that opens the file for reading

this opens the file for writing
but it also deletes the file
handle=FileOpen("filename.cvs", FILE_CSV|FILE_WRITE, ';');

to open a file for writing, without deleting the data
you must use this


handle=FileOpen("filename.cvs", FILE_CSV|FILE_READ|FILE_WRITE, ';');

seek to the end before you write the new data
FileSeek(handle, 0, SEEK_END);

hope that helps

oh yeah, the delimiter is like this

data;data;data;data;

many things are possible
  • #4
  • Sep 20, 2009 12:27am Sep 20, 2009 12:27am
Thanks for the swift and comprehensive replies. One other thing I forgot to ask was about determining when a given timeframe bar had completed (as this would initiate saving data to file). I seem to remember storing the bar open time (of bar 0) in a STATIC var and then whenever this value changes, I can then save bar 1 (ie T-1) to file (if appending).

Does that ring true with you guys ? Had a look and couldn't find specific examples. Any help appreciated !!
  • #5
  • Edited 6:59am Sep 20, 2009 6:57am | Edited 6:59am
You can use open time ok I guess, but I prefer bar number - it's a nice integer.
ps: Of course at closing time on Friday you have to do some additional programming if you don't want it left open over the weekend.
  • #6
  • Sep 20, 2009 9:53am Sep 20, 2009 9:53am
use this
iBarShift(NULL,timeframe,0)

lets say you wanna restict anything to a per bar basis

at the top
extern int timeframe=0;
int currentbar;

after init()
currentbar=iBarShift(NULL,timeframe,0);//this restricts ea from drawing when first placed on the chart, you can delete this for instant entry

in the rules inside of the start()

if (currentbar!=iBarShift(NULL,timeframe,0)&&more rules)
{
open trades, what ever;
currentbar=iBarShift(NULL,timeframe,0);
}

to insure i always get my trade, i also add this just before that code

int orders=Orderstotal();

then in my code i do this

Inserted Code
int orders=Orderstotal();
if (currentbar!=iBarShift(NULL,timeframe,0)&&more rules)
{
open trades, what ever;
if (orders>Orderstotal())currentbar=iBarShift(NULL,timeframe,0);
}

but ur not opening a trade, so you dont need that
  • #7
  • Sep 20, 2009 12:59pm Sep 20, 2009 12:59pm
You have used iBarShift with 0 as the param. I'm a little confused. Why is the 0 specified ? Does it have meaning or have you put it there just to represent anytime ? One would have thought that zero would represent the MT4 1970 clock start !?
  • #8
  • Sep 20, 2009 3:45pm Sep 20, 2009 3:45pm
0 is the current bar, it returns open time of current bar


Quoting TheGeneral
You have used iBarShift with 0 as the param. I'm a little confused. Why is the 0 specified ? Does it have meaning or have you put it there just to represent anytime ? One would have thought that zero would represent the MT4 1970 clock start !?
  • #9
  • Sep 20, 2009 4:25pm Sep 20, 2009 4:25pm
Thanks for the continued response on this but I am still having a problem getting my head around this.

I need to save data upon the completion of each new bar. Are you stating above that I should have a global DATETIME var which is passed to the iShift function and comparing the return value of that against zero (ie current bar) and if they are different, then I know I have some data to save ?

Apologies for being dense !!
  • #10
  • Sep 21, 2009 4:39am Sep 21, 2009 4:39am
yes, but its not zero

ibarshift returns the bars open time in seconds since 1970, so it will be a big number, each bar has a dif number
so soon as a new bar opens, it will save the data, then wait on another new bar to do it again

Quoting TheGeneral
Thanks for the continued response on this but I am still having a problem getting my head around this.

I need to save data upon the completion of each new bar. Are you stating above that I should have a global DATETIME var which is passed to the iShift function and comparing the return value of that against zero (ie current bar) and if they are different, then I know I have some data to save ?

Apologies for being dense !!
  • #11
  • Sep 21, 2009 5:25am Sep 21, 2009 5:25am
Quoting TheGeneral
Can anyone point me in the right direction by way of examples ? I think the biggest question mark in my mind is the determining if the file exists (Win API ?) and the append to the end of a file thing (MT4 only support FILE WRITE and FILE READ ?)
Try to do it with the python binding. http://sites.google.com/site/prof7bi...on-integration you can then just comfortably use python file IO functions while at the same time circumventing all MT4 limitations.

Inserted Code
#include <py26.mqh>

int init(){
  PyInitialize();
  PyExecute('f = open("\\server\share\foo.txt", "w")');
  // untested. Not sure about the backslashes, maybe escape them.
}

int start(){
  PyExecute('b = ' + Bid);
  PyExecute('f.write(str(b) + "\n")');
  PyExecute('f.flush()');
}

int deinit(){
  PyExecute('f.close()');
}
Something along these lines.

You can import modules in init() where you can place all functions that you need, the import path is the experts folder. You can also easily start threads that will keep running in the background if you want to make a small network server for IPC instead of doing file IO.
  • #12
  • Sep 21, 2009 3:28pm Sep 21, 2009 3:28pm
Guys,

Thanks for all the responses, they are appreciated. Not sure about Python, had nothing to do with it previously...

TC, in relation to iBarShift, the documentation states:

Search for bar by open time. The function returns bar shift with the open time specified.

This meant (to me) that you provide the function with the open time and the function returns the bar number backwards which has that time as its open. However, you state above that the function returns the bar open time. Am I missing something here ?
  • #13
  • Sep 21, 2009 3:45pm Sep 21, 2009 3:45pm
Quoting TheGeneral
Guys,
This meant (to me) that you provide the function with the open time and the function returns the bar number backwards which has that time as its open.
This is correct. iBarShift() returns the index number of the bar that can be used in iClose(), iOpen() and other indicators.
  • #14
  • Mar 17, 2010 4:42am Mar 17, 2010 4:42am
Hello TrendChaser,

you mentioned that you made a csv trade copier.. I am trying to build probably the same thing.

The Ea will read an old LOGFILE that I place in the experts/files folder
the EA will read the string and place the exact trades from the csv file.

ReadOldLog_Open=FileOpen("20100314.csv", FILE_CSV|FILE_READ, ';');

if(ReadOldLog_Open>0)
{ FileSeek(ReadOldLog_Open, 0, SEEK_SET);
Open_Order_Type=StrToInteger(FileReadString(""));
Open_Open_Time=StrToTime(FileReadString(""));
Open_Order_Symbol=FileReadString("");
// Open_Open_Price=StrToDouble(FileReadString(""));// Price is No concern!
Stop_Loss=StrToDouble(FileReadString(""));
Take_Profit=StrToDouble(FileReadString(""));
}


as of now, I can open the file, but I am not sure how this EA will read the correct data to place the trade.

Of course the EA will need to read the time-symbol-lot-direction SL TP
08:50:29 '******': instant order buy 1.00 EURUSD. at 1.3663 sl: 0.0000 tp

The purpose is to use an Old trade log and have the EA place trades at or around the same time (within Ext variable). and thats it.

to enter a trade:
if (log time is < current time +=ext variable)
place trade.

Can I assign an int value of 1 for Buy and 0 for Sell?

than in the "to enter a trade" if( Open_Order_Type>0) Buy and if(Open_Order_Type<1) Sell

I have no coding experience, but I am learning! any help would be nice.
  • #15
  • Last Post: May 14, 2023 9:39am May 14, 2023 9:39am
Quoting trendchaser
i used cvs files to make a trade copy ea, i can send, edit settings with cvs files, i can do bout anything with cvs files, i like teaching more than doing, il help you along if your up for it i was able to fully teach my self using the help in editor your question, to see if the file exists heres pasted from help int handle; string str; handle=FileOpen("filename.csv", FILE_CSV|FILE_READ); if(handle>0) { str=FileReadString(handle); FileClose(handle); } if handle is above 0, yes it exists also see the extension csv thats a error, so look for that...
Thank you so much TrendChaser.... your answer here helped me a lot. Appreciate it
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