If I have the following list:
https://pastebin.com/nqyf4yY5
How can I find the closest value to "89" in the "T[C]" column and its corresponding value in the "DH,aged-DH,unaged (J/g)" column?.
Thank you in advanced,
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3 Answers
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Given your data
data[[5]] // InputForm
(* {"Time(s)", "T[C]", "K(T)=k^(1/n)",
"dx/dT", "x(t)",
"DH,aged-DH,unaged (J/g)",
"Check dx"} *)
values = data[[6 ;;]];
You are asking for data that corresponds to headers for columns {2, 6}.
The entry for the value of T[C] (column 2) closest to 89
entry = values[[Position[values[[All, 2]],
Nearest[values[[All, 2]], 89][[1]]][[1, 1]]]]
(* {3.87*10^-6, 89.2592, 5.13099, 0.0107504, 0.0102723, 0.0123268, 0.0000417117} *)
The desired values are
entry[[{2, 6}]]
(* {89.2592, 0.0123268} *)
answered May 3, 2020 at 19:35
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$\begingroup$ Bob, for some reason your code is not working. What does "values" do? it shows as a not defined variable. $\endgroup$– JohnCommented May 3, 2020 at 20:40
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$\begingroup$ I forgot to copy definition. Added. $\endgroup$ Commented May 3, 2020 at 20:44
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$\begingroup$ thank you that works!. Last quick question if you dont mind: I realized that they way I have my "data" is in
TableFormso literally when I inpurdataI will get rows and columns as if it were an excel file, where the headers are in the 5 row the data starts in the 6 row. When I pasted the input fromdatait looks like what I pasted in here where the output is not inTableForm. Is there any way to transform mydatato into how I have it in here?.The reason I ask if because it seems that when it is as in TableForm the code does seem to work. Thank you $\endgroup$– JohnCommented May 3, 2020 at 21:07 -
1$\begingroup$ I do not understand your comment. However, in general since
TableFormis a wrapper and intended only for display, you do not want it included in a definition ofdata. That is rather thandata = TableForm[datavalues]you would instead useTableForm[data = datavalues]. That way the definition ofdatadoes not contain the wrapper. $\endgroup$ Commented May 3, 2020 at 21:37 -
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data = Import["~/Downloads/data.txt"] // ToExpression // Part[#, 6 ;;] &;
nf = Nearest[data[[All, 2]] -> {"Index", "Element"}];
data[[nf[89][[1, 1]]]]
(* {3.87*10^-6, 89.2592, 5.13099, 0.0107504, 0.0102723, 0.0123268, 0.0000417117} *)
answered May 3, 2020 at 19:37
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$\begingroup$ Rohit, I am a little new to Mathematica and since I have my data already in mathematica as "data" and and do not need to imported, when I put
data // ToExpression // Part[#, 6 ;;] &;it does not work. What should I put her to make it work if I already have the data and I don't need to import it?. Thank you $\endgroup$– JohnCommented May 3, 2020 at 20:45 -
1$\begingroup$ @John If the data is already a
List, then you do not need theToExpression. Not sure if you need thePart[#, 6::]&, depends on the list structure. $\endgroup$ Commented May 3, 2020 at 21:47
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With your data, assuming the column headings are in row 5:
data[[5]]
(* {"Time(s)","T[C]","K(T)=k^(1/n)","dx/dT","x(t)","DH,aged-DH,unaged (J/g)","Check dx"} *)
... find the column numbers for columns "T[C]" and "DH,aged-DH,unaged (J/g)":
{c1, c2} = Flatten@{
Position[data[[5]], "T[C]"],
Position[data[[5]], "DH,aged-DH,unaged (J/g)"]};
It's easier to search the data without the extra rows at the top. When there are multiple values that match, we find only the first one. Get the nearest value and the matching column:
values = data[[6 ;;]];
v = 89.;
First@Extract[values[[All, {c1, c2}]],
Position[values[[All, c1]], First@Nearest[values[[All, c1]], v]]]
(* {89.2592, 0.0123268} *)
T[C]?{"Delta t (s)", 1.*10^-8}, {"q (K/s)", 1000}, {""}, {""}, {"Time(s)", "T[C]", "K(T)=k^(1/n)", "dx/dT", "x(t)", "DH,aged-DH,unaged (J/g)", "Check dx"}$\endgroup$90.01up to89.2592(those in the second element of the list). The "DH,aged-DH,unaged (J/g)" column would be the values that start in0.0000159219up to0.0123268(those in the sixth position of the lists). I hope that helps clarify it. $\endgroup$