python - Matplotlib rendering right

Question

I have a basic function that does a function and I want to plot it out with Matplotlib but it doesn't work. It even prints out the correct list but still Matplotlib wont show it right

Here's my code:
And what it outputs:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]
[7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1]

from matplotlib import pyplot as plt

number = 14
count = 0

dev_x = []
dev_y = []

plt.plot(dev_x, dev_y)

while number != 1:
    if(number % 2 == 0):
        _number = number / 2
        number = _number
        print(number)
        dev_y.append(int(number))
        dev_x.append(int(count))
        count = count + 1
    else:
        _number = number * 3 + 1
        number = _number
        print(number)
        dev_y.append(int(number))
        dev_x.append(int(count))
        count = count + 1

    print(count)
else:
    count = count + 1
    print(dev_x)
    print(dev_y)
    plt.show()
    print("DONE")

print(number)

标签： pythonmatplotlib

Answer 1

you are trying to plot dev_x and dev_y before populating them. You need to call the plotting function after adding all coordinates

from matplotlib import pyplot as plt

number = 14
count = 0

dev_x = []
dev_y = []



while number != 1:
    if(number % 2 == 0):
        _number = number / 2
        number = _number
        print(number)
        dev_y.append(int(number))
        dev_x.append(int(count))
        count = count + 1
    else:
        _number = number * 3 + 1
        number = _number
        print(number)
        dev_y.append(int(number))
        dev_x.append(int(count))
        count = count + 1

    print(count)
else:
    count = count + 1
    print(dev_x)
    print(dev_y)
    plt.show()
    print("DONE")
    enter code here

## move this line here
plt.plot(dev_x, dev_y) 
print(number)