CODEWITHSUNDEEP
pythonmaxaudio
ddbg
ddbg

Reputation: 37

Max() function using python from loop

I am trying to write a program to determine the maximum value of a sample from a sound. The loop returns the values of all the samples, however I cannot figure out how to print the largest.

def largest():
f=pickAFile()
sound=makeSound(f)
for i in range(1,getLength(sound)):
  value=getSampleValueAt(sound,i)
print max([value])

Upvotes: 0

Views: 7051

Answers (3)

Sylvain Leroux
Sylvain Leroux

Reputation: 52040

Don't remember we are dealing with audio data. With possibly millions of samples. If you want to stick with something efficient both in space and time, you have to rely on the far less sexy:

def largest():
    f = pickAFile()
    sound = makeSound(f)
    max = getSampleValueAt(sound, 1) # FIX ME: exception (?) if no data
    idx = 2
    while idx < getLength(sound):
        v = getSampleValueAt(sound, i)
        if v > max:
            max = v
        i += 1

    print max

Generator-based solution are efficient too in term of space, but for speed, nothing could beat a plain-old imperative loop in Python.

Upvotes: 1

Vizjerei
Vizjerei

Reputation: 1030

Didn't test it but maybe:

def largest():
 f=pickAFile()
 sound=makeSound(f)
 value = [ getSampleValueAt(sound,i) for i in range(1,getLength(sound)) ]
 print max(value)

Upvotes: 0

matsjoyce
matsjoyce

Reputation: 5844

Try:

def largest():
    f = pickAFile()
    sound = makeSound(f)
    value = []
    for i in range(1, getLength(sound)):
      value.append(getSampleValueAt(sound, i))
    print max(value)

Or

def largest():
    f = pickAFile()
    sound = makeSound(f)
    print max(getSampleValueAt(sound, i) for i in range(1, getLength(sound)))

With your code, value is overwritten at each iteration. If you make a list with all the values, you can then find the max using max.

Also see:

Upvotes: 3

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