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I tried to solve some equation for different values of parameter t and put results into array. Then I wanted to write this data into a txt-file. So i did it with Write function. But strings in this file look like:

{{y -> -300.339}}

Are there some parameters of Write function for numbers (with sign) writing only?

Array[f, 1000]

x := 2
z := 1
v := 0.98
T := 10
dt := T/1000

For[i = 0, i < 1000, 
 i++, f[i] = Solve[-T/2 + i*dt - y == Sqrt[x^2 + (z - v*y)^2], y]]

I tried this one, but it doesn't help:

For[i = 0, i < 1000, 
 i++, { a = Solve[-T/2 + i*dt - y == Sqrt[x^2 + (z - v*y)^2], y], 
  f[i] /. a}]
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  • 1
    $\begingroup$ It is not clear what you are asking. If your results are in the form of Rule expressions you will need to convert them to bare numbers. See for example: (1616091), (8355218), (6669) $\endgroup$ – Mr.Wizard Feb 8 '15 at 11:17
  • $\begingroup$ Okay, that's a code. Array[f, 1000] x := 2 z := 1 v := 0.98 T := 10 dt := T/1000 For[i = 0, i < 1000, i++, f[i] = Solve[-T/2 + i*dt - y == Sqrt[x^2 + (z - v*y)^2], y]] I tried this one, but it doesn't help: For[i = 0, i < 1000, i++, { a = Solve[-T/2 + i*dt - y == Sqrt[x^2 + (z - v*y)^2], y], f[i] /. a}] $\endgroup$ – newt Feb 8 '15 at 11:34
  • $\begingroup$ Please use the edit link below your question to include code examples. $\endgroup$ – Mr.Wizard Feb 8 '15 at 11:35
  • $\begingroup$ I posted an answer. I hope the examples help you. I am not sure what you intend for f so I left it out. If you wish to save the definition of f itself please see: (2008) $\endgroup$ – Mr.Wizard Feb 8 '15 at 11:43
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Please try this code:

x := 2
z := 1
v := 0.98
T := 10
dt := T/1000

Table[
 y /. Solve[-T/2 + i*dt - y == Sqrt[x^2 + (z - v*y)^2], y][[1]],
 {i, 0, 999}
]
{-300.33859829722434`, -299.8391603699061`, -299.3397243096371`, 
 -298.8402901257249`, . . ., 2.506139642749351`, 2.5124784155139106`}

You should be able to Export that as a plain list of numbers. Be aware that I extract only the first solution, should more than one exist, but I am guessing that is OK.

If you need a table including the i values:

Table[
 {i, y /. Solve[-T/2 + i*dt - y == Sqrt[x^2 + (z - v*y)^2], y][[1]]},
 {i, 0, 999}
]
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