Converting string to datetime

Im doing something wrong here and getting incorrect output.

At one point of my EA im saving a datetime to a string variable as something like this:

pointA = 1303867800

Now at some later point i need to convert that back to a datetime so that i can use it to create a rectangle object on the chart so im using :

pointA = StrToTime(pointA)

After doing this the variable becomes:

pointA = 1303948800

Which as you can see is different from the original above - im probably doing something silly wrong if anyone can help getting my original DateTime variable to a string and then BACK to DateTime, much appreciated.

thx

not enough code to debug. it looks like your string is being updated somewhere along the way with a new value since the value when you send it back through strtotime has a larger number indicating a more recent time value.

it does look that way but its quite odd - im using the following line to debug and within the line its incorrect:


Output is:

you are definitely doing something wrong.

StrToTime should be receiving a string in the format "yyy.mm.dd hh:mm", but in your example the pointA string just equals some number.

i think you are likely going about this all wrong and making things difficult for yourself, but nonetheless have a look at the code that works below


example output gives : 2011.04.28 18:30:04 nbTestingOthersIndi EURUSD,M1: pointA = 2011.04.28 10:30 after convert to time: 1303986600

ok i see your point - but this is the full story -

i have a first EA saving this TimeDate to a file - therefore obviously it saves as a string:


Therefore when the 2nd EA gets this data from the file it looks like "1303867800"

Are you saying when i save pointA to file i should use "TimeToStr" function ? Will that save it correctly so that when it comes back its correct ?

yeah of course.

datetime is basically an integer.

you are writing an integer value to a file in string format e.g. "123456789", then you are reading from the file this number and then pushing it to the strtotime function as that string of numbers instead of the pseudo-sentence format that strtotime expects.

timetostr and strtotime convert back and forth between datetime numbers and pseudo-date sentences. their entire purpose is to be able display a datetime value in a human-readable format, or take a human-readable formatted string containing date and time values and convert this to a computer useable datetime (integer) value.

either take the datetime number, convert it to the date string pseudo-sentence with timetostr, write this to file... then later read this pseudo-sentence back and convert back into a datetime with timetostr.

or, the more logical way, take the datetime number, IntToStr and write the string to file... later read the string from the file, then convert back to int with StrToInt.

completely avoid the pointless timetostr/strtotime funcs which are more useful for spitting out into human-readable formats and have no positive usefulness to the computer.

i should clarify a bit further. what you have done you would not be able to do in a proper programming environment, and you have come stuck due to mql dealing with certain situations liberally instead of strictly enforcing type conventions.

what you appear to have effectively done is this :

take an int, writetosomefile(integer) [at this point mql automagically converts the integer into a string representation of this number for you, but really it shouldn't... this is where you have become tripped-up]... readfromfile(string), StringDateSentenceToDatTime(string)

edit : above should actually be - take an int value and directly read it into a string variable [mql converts this for you automatically but shouldn't, and this is where you have been caught-out], write string to file, read string from file, convert date formatted string to datetime

this is spitting out a garbage value because you aren't passing it the correct stuff to begin with. if mql was half-serious it would puke when you try to read the datetime integer value into a string variable and instead should force you to manually do this conversion yourself so that you actually know precisely what value is what at all times instead of letting you hang yourself.

to watch it in action is to see something like this :

convert datetime 123456789 to string "123456789"
write to file : string "123456789"
read from file : string "123456789"
convert string "123456789" which is meant to be formatted with date and time data to garbage datetime value 987654167

but, what you THINK is happening is this :

convert datetime 123456789 to string formatted as date and time data "yyyy.mm.dd hh:mm"
write to file "yyyy.mm.dd hh:mm"
read from file "yyyy.mm.dd hh:mm"
convert string "yyyy.mm.dd hh:mm" to datetime value 123456789

what you WANT to happen is this :

convert datetime 123456789 to string "123456789"
write to file "123456789"
read from file "123456789"
convert string "123456789" to int (which is the same as datetime) 123456789

or, if this doesn't work you can do this which is more like what you intended to do :

convert datetime 123456789 to date formatted string "yyyy.mm.dd hh:mm" (using TimeToStr)
write string "yyyy.mm.dd hh:mm" to file
read string "yyyy.mm.dd hh:mm" from file
convert date formatted string "yyyy.mm.dd hh:mm" to datetime 123456789

probably can't be much clearer than that.

thx heaps for the explanation - appreciate it .

only thing is i cant find the IntToStr in the documentation ?

oh ffs!!! sorry dude, i get myself a little backwards sometimes since i write code in a few different languages. i'm possibly getting confused with what you are doing with what variables. it can greatly help in these situations to give more meaningful names to your variables such as "PointAString" or "sPointA"... doubles as "tempdouble" or "dtemp" etc etc. without seeing the variable declarations you have used to define the variables and their types i'm taking guesses as to what you have done exactly.

to answer your question looking in the help file i see there actually isn't an intostr function, and you can simply assign a string variable an integer number and mql automagically converts it for you. in a proper programming environment stuff like this would require calling a dedicated function that specifically converts an integer to a string, and in this way you can't get mixed-up with what variable X holds and what variable Y holds as the compilers fall-over if you try to mix and match different data types.

in summary : i'm getting confused. you will figure it out, just keep in mind if you are reading or writing a string version of a number, or a date formatted string version of a datetime number