invalid filename saving figure

I am trying to save this figure using the following code, however I keep getting the error "invalid filename".

Str2 consists of a combination of text and values, to create a unique name, corresponding to the figure at hand. However, something, somewhere goes wrong. I have tried to remove the .png and add it to the saveas command. I have tried to name my figure, like f=figure(), but I cannot discover my error. Any solutions?

    figure(2)
    hold on
    plot(output_time,Principal_stress_fatigue_fy_mx/10^6)
    ylabel('equivalent stress [MPa]')
    xlabel('time [s]')
    grid
    str2="Figure2"+ VTRIM + bank_angle + roll_rate + AC_mission_type(j)+".png"
    saveas(gcf,str2)

[Abderrahim. B]

Hi!

Can you tell us what is the data type of VTRIM , bank_angle , roll_rate

[Rose]

VTRIM=80        %kts
bank_angle=45   %deg
roll_rate=10    %deg/s

[Walter Roberson]

and AC_mission_type(j) ?

By the way you should either be using fixed width formats with 0 fill, or else you should be using delimiters between the parts. for example bank rate 4, roll 28 would generate the same name as bank rate 42 roll 8

[Rose]

The AC_mission_type is included in a for loop. So the plots will be created for the combination of bank angle, roll rate and VTRIM for each of these mission types.

AC_mission_type ={ 'design','extended', 'maximum alternate'}

It is no problem for mee that 428 could mean 2 things, as I only assume a couple of predefined scenario's. But thank you for the advice!

[Bruno Luong]

I hope j is scalar, otherwise str2 is an array.

Could it be that the absolute path + filename is too long for the OS filesystem?

[Walter Roberson]

Could you show us an example of the str2 when there is a failure ?

[Rose]

to answer both your questions:

j=1:length(AC_mission_type)

and:

Str2=

"Figure2804510design.png"

[Walter Roberson]

As an experiment, try

    saveas(gcf, char(str2))

[Rose]

it works! Thank you!

[Walter Roberson]

Odd. You filled out R2021a as your release, but string() was supported for that parameter in R2021a. R2017a was the last release that did not support string() for that parameter.