Print value result on same line (Python)

Question

I have this to do:

import psutil
import read_config

mem = psutil.virtual_memory()

print('Total RAM: ', (round(mem[0] / (1024 * 1024))), '(MB)')  # total

ram_usage = read_config.ram_usage

while ram_usage is True:
    mem = psutil.virtual_memory()
    print('Used RAM: ', (round(mem[3] / (1024 * 1024))), '(MB)', end="")  # used

The problem is that if I execute, the output is this:

Total RAM:  3949 (MB)
Used RAM:  3069 (MB)Used RAM:  3069 (MB)Used RAM:  3069 (MB)Used RAM:  3069 (MB)Used RAM:  3069 (MB)

How can I solve the Used RAM problem ? I want to print on the second line just value of used RAM, not to print the line everytime the condition is satisfied.

Thanks

changing `while` to `if` would certainly solve your problem wouldn't it — FlyingTeller, Feb 23 '18 at 14:37
Are you trying to continuously monitor ram used, and update display accordingly ? — Faibbus, Feb 23 '18 at 14:38
@FlyingTeller yes, it works. Thanks. But what if I have to use while ? — lucians, Feb 23 '18 at 14:38
@Faibbus Yes, exactly. I would like to see just the value changing. — lucians, Feb 23 '18 at 14:39
@Link so you do want the loop, but only print when the value has changed? — FlyingTeller, Feb 23 '18 at 14:39
[Have a look at this question](https://stackoverflow.com/questions/3173320/text-progress-bar-in-the-console). You can adopt the continous update of the same outputline from there. — Igl3, Feb 23 '18 at 14:41
Then you have to do something more complicated, first keep track of the previous value (to update only when the value changes), and then either make a GUI or https://stackoverflow.com/questions/6840420/python-rewrite-multiple-lines-in-the-console — Faibbus, Feb 23 '18 at 14:42
@Faibbus that's slightly overkill for 1 line, when you can do `print('Used RAM: ', (round(mem[3] / (1024 * 1024))), '(MB) ', end="\r")`. The only issue is to print enough spaces to be sure to delete all the characters from the previous print if printed memory is smaller — Jean-François Fabre, Feb 23 '18 at 14:47
@Jean-FrançoisFabre this is pretty close to the result. The problem is that it keep refreshing the result (RAM used line). — lucians, Feb 23 '18 at 14:49
@Link I have added another link. Also note that you have a CPU active loop here, and also infinite (booleans are immutable, you're testing a kind of copy of your flag) — Jean-François Fabre, Feb 23 '18 at 15:00
@Jean-FrançoisFabre thanks. It's what I am searching. From what other users said it's a little complex as task. — lucians, Feb 23 '18 at 15:03

score 1 · Answer 1 · answered Feb 23 '18 at 14:43

To detect if the value has changed, simply save the old value and then print conditionally:

old_mem = 0
while ram_usage is True:
    mem = psutil.virtual_memory()
    if mem[3] != old_mem:
        old_mem = mem[3]
        print('Used RAM: ', (round(mem[3] / (1024 * 1024))), '(MB)')

This would however detect very small changes. If you just want to print when the displayed value would change, first convert to MB and then compare:

old_mem = 0
while ram_usage is True:
    mem = psutil.virtual_memory()
    mem_mb = round(mem[3] / (1024 * 1024))
    if mem_mb != old_mem:
        old_mem = mem_mb
        print('Used RAM: ', mem_mb, '(MB)')

Yes, this can be already a step ahead, but the answer is more like the above comments, for example, loading bar. — lucians, Feb 23 '18 at 14:46

Print value result on same line (Python)

1 Answers1