eval function using in load command

whay I'm getting this error when I use eval function to make it dynamic:

dp=500;flow='Q1',d=16/1000;try_num=1;,.....
load(eval(['D:\45deg_light_sheet_dp' num2str(dp) '_' num2str(flow) '_pipeID' num2str(d*1000) 'mm\try' num2str(try_num) '\loc_vel_ID' num2str(d*1000) 'mm_thresh' num2str(thresh_pln1) '_' num2str(flow) '_dp' num2str(dp) '_pln1_try' num2str(try_num) '_between two planes x1=' num2str(Xl_pln1) '-x2=' num2str(Xr_pln1) '_45deg_lightsheet_bin_new_name_variables.mat']));

Error: Invalid use of operator.

[Stephen23]

Why are you using EVAL()? it serves absolutely no purpose in your code.

Note that to make your code more robust, you should LOAD() into an output variable:

S = load(..);

Answer 1

[Steven Lord]

There is absolutely no need to use eval here. You're building a file name, not building code to evaluate.

dp=500;
flow='Q1';
d=16/1000;
try_num=1;
thresh_pln1 = 42; % You omitted this
Xl_pln1 = 999; % and this
Xr_pln1 = 314159; % this too
filename = ['D:\45deg_light_sheet_dp' num2str(dp) '_' num2str(flow) '_pipeID' num2str(d*1000) 'mm\try' num2str(try_num) '\loc_vel_ID' num2str(d*1000) 'mm_thresh' num2str(thresh_pln1) '_' num2str(flow) '_dp' num2str(dp) '_pln1_try' num2str(try_num) '_between two planes x1=' num2str(Xl_pln1) '-x2=' num2str(Xr_pln1) '_45deg_lightsheet_bin_new_name_variables.mat']

filename = 'D:\45deg_light_sheet_dp500_Q1_pipeID16mm\try1\loc_vel_ID16mm_thresh42_Q1_dp500_pln1_try1_between two planes x1=999-x2=314159_45deg_lightsheet_bin_new_name_variables.mat'

You could use this filename by using the functional form of load, as load(filename).