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# Generate a 440 Hz square waveform in Pygame by building an array of samples and play
# it for 5 seconds. Change the hard-coded 440 to another value to generate a different
# pitch.
#
# Run with the following command:
# python pygame-play-tone.py
from array import array
from time import sleep
import pygame
from pygame.mixer import Sound, get_init, pre_init
class Note(Sound):
def __init__(self, frequency, volume=.1):
self.frequency = frequency
Sound.__init__(self, self.build_samples())
self.set_volume(volume)
def build_samples(self):
period = int(round(get_init()[0] / self.frequency))
samples = array("h", [0] * period)
amplitude = 2 ** (abs(get_init()[1]) - 1) - 1
for time in xrange(period):
if time < period / 2:
samples[time] = amplitude
else:
samples[time] = -amplitude
return samples
if __name__ == "__main__":
pre_init(44100, -16, 1, 1024)
pygame.init()
Note(440).play(-1)
sleep(5)
@TrumpetDude

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@TrumpetDude TrumpetDude commented Dec 3, 2016

I believe there is a typo in line 25, saying xrange instead of range. After fixing it, the tone played. How do I send the correction as a pull request/revision?

@danharrisondev

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@danharrisondev danharrisondev commented Apr 14, 2017

@TrumpetDude That is not a typo. In Python 2 we have both range and xrange. The difference is that range returns an enumeration whereas xrange returns an iterator.

In Python 3 xrange was renamed to range replacing the original range method.

There are many subtle changes like this between Python 2 and 3 that you might like to be aware of, see the What's New In Python 3.0 article for more examples :)

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