For loop print statement problem

[Mattyp77]

Why is it that when i write this code..
for i in range(5):
print('*', end = ' ')
time.sleep(.5)

it works in the pycharm console. That is it sequentially prints a * then sleeps for a half a second and prints another star directly after the last star and repeats 5 times.
Thus giving the impression of the computer is loading or computing or whatever.

But when I save the file and run it in a terminal it doesnt work like that. instead it acts more like this:
time.sleep(2.5)
print('*****')

it sleeps for the duration of the loop then prints the five stars all at once. What gives?

 

[menator01]

Use flush=True in the print function

from time import sleep

for i in range(5):
    print('*', end='', flush=True)
    sleep(1)

 

[VBService]

a slightly different approach

import sys
from time import sleep

for i in range(5):
    sys.stdout.write('*')
    sys.stdout.flush()
    sleep(.5)

import sys
from time import sleep

for _ in range(5):
    print('*', end='')
    sys.stdout.flush()
    sleep(.5)

 

[VBService]

and finally in python you can do it even like that ...
... some times syntax in python is poquito loco

from time import sleep

_ = [print('*', end='', flush=True) or sleep(.5) for _ in range(5)]

 

[menator01]

Playing around a bit

from time import sleep

string = 'This is a string'
def stars(arg):   
    return [print('*', end='', flush=True) or sleep(.15) for _ in range(arg)]


stars(len(string))
print(f'\n{string}')
stars(len(string))
print('\n')

 

[VBService]

Playing around a bit

from time import sleep

string = 'This is a string'
def stars(arg):
return [print('*', end='', flush=True) or sleep(.15) for _ in range(arg)]


stars(len(string))
print(f'\n{string}')
stars(len(string))
print('\n')

nice one ...

but, like I said ...

syntax in python is poquito loco

from time import sleep

string = 'This is a string'
def stars(arg):  
    return [print('*', end='', flush=True) or sleep(.15) for _ in range(len(arg))]


[(lambda s: (stars(s), print(f'\n{s}'), stars(s)))(string)]

 

[menator01]

I like it.

 

[VBService]

and this one...
completely illegible, don't write code like that, shown only for demonstration purposes

from time import sleep as p
s='This is a string'
[(print('*',end='',flush=True) or p(.15))for _ in s],print('\n'+s),[(print('*',end='',flush=True) or p(.15))for _ in s]

 

[Mattyp77]

and finally in python you can do it even like that ...
... some times syntax in python is poquito loco

from time import sleep

_ = [print('*', end='', flush=True) or sleep(.5) for _ in range(5)]

Geez if you don't say. Mind boggled

 

[Mattyp77]

Wow some strange stuff indeed. So what exactly is this type of called?

_ = [print('*', end='', flush=True) or sleep(.5) for _ in range(5)]

An expression or comprehension or something. Or just weird? lol

 

[menator01]

yes list comprehension

 

[Mattyp77]

yes list comprehension

would you mind breaking this down a bit for me? how do you fit a print statement into a list? And how does the or fit in?

 

[menator01]

List comprehension is a short way to put a for loop on one line.
As in most languages the or is saying either print this or print that.
It just running the sleep command.
or can be used in inputs as well as a default value. For example

var = input('Type something: ') or 'Print default value'
print(var)

If you type something and press enter, what's typed will print.
If you just press enter without typing anything the default value will display.

 

[Mattyp77]

List comprehension is a short way to put a for loop on one line.
As in most languages the or is saying either print this or print that.
It just running the sleep command.
or can be used in inputs as well as a default value. For example

var = input('Type something: ') or 'Print default value'
print(var)

If you type something and press enter, what's typed will print.
If you just press enter without typing anything the default value will display.

oh so if the value is false it will use the other? But in our case its actually using both right? And the sleep statement actually becomes a value inside the list?

 

[Mattyp77]

i have smoke coming out my ears. I kinda get it but I kinda dont. So weird