Mathematica Interpolation function error

[Youssi]

TL;DR

Interpolation error : :inder: The order-2 derivative of {1651.15,0.129739} is not a tensor.

Hello everyone,
I am relatively new to Mathematica, and I am encountering an issue when trying to interpolate numerical data imported from an Excel file.
Here are the steps I've taken:
I imported the numerical data from an Excel file into Mathematica.
I attempted to interpolate the data using the command:
[Lambda]Interp = Interpolation[lambda, InterpolationOrder -> 2];
However, I encountered the following error:
Interpolation::inder: The order-2 derivative of {1651.15,0.129739} is not a tensor.
As a new user, I'm unsure how to correct this issue. I would greatly appreciate any guidance or suggestions on resolving this error. If there are alternative approaches to achieve the interpolation, please feel free to share them.

Thank you in advance for your help!

 

[DrClaude]

How do you import the data?

 

[Youssi]

This the command that i use to import data :
Lambda= Import["C:\\Users\\Documents\\Modélisation\\1_\\mathematica\\condu_therm_rer.xlsx"];
and this is how the data are displayed:
{{{707.637, 0.0556025}, {1280.52, 0.092702}, {1415.35, 0.0927435}, {1651.15, 0.129739}, {1887.03, 0.148273}, {2055.5, 0.166787}, {2257.63, 0.194541}, {2358.68, 0.213034}, {2527.14,0.231548}, {2560.66, 0.277712}, {2661.67, 0.305435}, {2729.01, 0.323918}, {2796.23, 0.370092}, {2930.91, 0.407057}, {2964.39, 0.462452}, {3132.67, 0.527119}, {3132.48, 0.573273}, {3300.75, 0.637941}, {3300.56, 0.684095}, {3401.5, 0.73028}, {3536.33, 0.730321}, {3637.83, 0.638044}, {3941.43, 0.582753}, {4110.08, 0.555112}, {4177.65, 0.51821}, {4346.19, 0.518262}, {4548.44, 0.518324}, {4683.08, 0.56452}, {4851.39, 0.619956}, {4851.12, 0.684572}, {4884.6, 0.739967}, {4951.87, 0.776911}, {4985.46, 0.804613}}}

 

[renormalize]

This the command that i use to import data :
Lambda= Import["C:\\Users\\Documents\\Modélisation\\1_\\mathematica\\condu_therm_rer.xlsx"];

Mathematica imports multiple Excel worksheets all at once in the form of a list: {Sheet1, Sheet2, ...}. Since you only have one sheet, change your import statement to:
Lambda=Import["C:\\Users\\Documents\\Modélisation\\1_\\mathematica\\condu_therm_rer.xlsx"][[1]];
to extract your single sheet from the list. This removes the outermost set of braces and allows the interpolation to run successfully.

 

[Youssi]

Mathematica imports multiple Excel worksheets all at once in the form of a list: {Sheet1, Sheet2, ...}. Since you only have one sheet, change your import statement to:
Lambda=Import["C:\\Users\\Documents\\Modélisation\\1_\\mathematica\\condu_therm_rer.xlsx"][[1]];
to extract your single sheet from the list. This removes the outermost set of braces and allows the interpolation to run successfully.

Thank you very much! It worked.