Simple For Loop
for i in range (1, 5): #Start value, Exit value (loop won't run with this value as it exits, so needs to be desired final value + 1)
print i:
Will output: 1 2 3 4
Reverse Loop
for i in range (5, -1, -1): #Start value, Exit value (loop won't run with this value as it exits, so needs to be desired final value + 1), adjust value
print i:
Will output: 5 4 3 2 1 0
Nested For Loops
for level in xrange(255, -1, -1):
for index in xrange(0, 24):
led_values[index] = level
bus.write_i2c_block_data(PCA9626_ADDRESS, (0x80 | PCA9626_REG_PWM0), led_values)
time.sleep(0.01)
USEFUL?
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6 months ago
How does the “While” command work? How can I set a particular number of times for a loop to run then exit?
2 months ago
Here is an example I use on some LED’s
set a counter, initiate the while, increment the counter in the loop.
It is the indenting that defines the while loop.
I am new at this so excuse the inelegance.
i=0
while i< 200:
IO.output(6,1)
time.sleep(1)
IO.output(5,False)
time.sleep(1)
i=i+1
if IO.input(21) ==0:
emerg_pgm_term()
break
print(" Loop completed is",i)
IO.output(4,False)
IO.output(5,False)
IO.output(6,False)
IO.output(5,0)
IO.output(20,0)
IO.output(19,0)
IO.output(20,0)
print('loop completes normally. Program terminates')