Problem 71. Read a column of numbers and interpolate missing data

Created by Cody Team
Appears in Remove Rows and Columns

Difficulty:Rate

Solve Later
Add To GroupÃ‚

Given an input cell array of strings s, pick out the second column and turn it into a row vector of data. Missing data will be indicated by the number 9999. If you encounter missing data, you should perform linear interpolation to the nearest accurate data points (missing data will not occur in the first or last element).

The first row is always descriptive text. So if the input cell array s is

 s = { ...
    'Day  Temp'
    '  1   -5'
    '  2   19'
    '  3   1'
    '  4   9999'
    '  5   3'};

then the output variable t is the following row vector.

 t = [-5 19 1 2 3];

Here's an example of real-world data.

Solve

Solution Stats

7504 Solutions
2314 Solvers

Last Solution submitted on Feb 20, 2025

Last 200 Solutions

Problem Comments

9 Comments

9 Comments

Show 6 older comments

Umur Ulas Harman on 31 Jul 2020

This is working still would be appreciated for enhancement.

function t = read_and_interp(s)
s=strtrim(s);
row_num=numel(s);
counter=1;
for i=2:row_num
splitted=strsplit(s{i});
temp1=splitted(1);
temp2=splitted(2);
r(counter)=str2double(temp1);
r(counter+1)=str2double(temp2);
counter=counter+2;
end
first_column=r(1:2:end)
second_column=r(2:2:end)
if find(second_column==9999)>=1
first_column(find(second_column==9999))=[];
missed=find(second_column==9999);
second_column(find(second_column==9999))=[];
missed_value=interp1(first_column,second_column,missed)
second_column=r(2:2:end);
second_column(find(second_column==9999))=missed_value;
t=second_column
else
t=second_column
end

Ahmed Nazir on 1 Oct 2020

Good Problem

beware of splitting.

solution:
https://github.com/AhmedNazir/MatlabCody/blob/master/read_and_interp.m

Peter on 18 Aug 2023

Interesting!

Solution Comments

Show comments

Problem Recent Solvers2314

Problem Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Problem 71. Read a column of numbers and interpolate missing data

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers2314

Suggested Problems

More from this Author96

Problem Tags

Community Treasure Hunt

Problem 71. Read a column of numbers and interpolate missing data

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers2314

Suggested Problems

More from this Author96

Problem Tags

Community Treasure Hunt

Players