询问用户（是/否）是否显示情节的问题。 是否使用（if/else）语句运行图形代码块

Question

I want to ask a user if they would like to see a certain graph. If they say "yes," I want my block of plot code to run. If they say "no," I want it to return None and go to the next question.

When I run my cell and input a 'yes' it just goes to the next question. The plot code works outside of the if statement. I am on a mac using Jupyter Notebook, running an Anaconda supported Python environment.

yeses=['yes','Yes','YES','y','Y'] 
nos=['no','No','NO','n','N']

p = input("Would you like to see the signal pattern of the song? (yes/no): ")
f = input("Would you like to see a plot of all the frequencies used in this song? (yes/no): ")
s = input("Would you like to see a spectrogram of the song? (yes/no): ")

if p in yeses:
    plt.subplot(2,1,1)
    plt.plot(time, sound[:,0], 'r')
    plt.xlabel("time, s [left channel]")
    plt.ylabel("signal, relative units")
    plt.subplot(2,1,2)
    plt.plot(time, sound[:,1], 'b')
    plt.xlabel("time, s [right channel]")
    plt.ylabel("signal, relative units")
    plt.tight_layout()
    plt.show()
else:
    return None

Answer 1

I assume you typed: yes CTRL-ENTER

Maybe you received "yes\n" ? Use repr(p) to diagnose, and p.rstrip() to fix, stripping any trailing newlines.

---

You wrote

yeses = ['yes', 'Yes', 'YES', 'y', 'Y']

You could more concisely use

yeses = ['yes', 'y']

and rely on p.lower() to uniformly downcase all user inputs.

Write a tiny helper function if the code does that repeatedly.