Tính lãi suất kép

tinh_lai_suat_kep.py

import matplotlib.pyplot as plt

lai_suat_theo_ky_han = [
    {
        "ky_han": 1,
        "lai_suat": 0.037
    },
    {
        "ky_han": 2,
        "lai_suat": 0.038
    },
    {
        "ky_han": 3,
        "lai_suat": 0.039
    },
    {
        "ky_han": 5,
        "lai_suat": 0.043
    },
    {
        "ky_han": 6,
        "lai_suat": 0.049
    },
    {
        "ky_han": 12,
        "lai_suat": 0.052
    },
    {
        "ky_han": 18,
        "lai_suat": 0.054
    },
    {
        "ky_han": 21,
        "lai_suat": 0.055
    },
    {
        "ky_han": 24,
        "lai_suat": 0.056
    },
    {
        "ky_han": 36,
        "lai_suat": 0.058
    },
]


def tinh_lai_kep(tien_goc: float | int, lai_suat: float, ky_han: int, thoi_gian_gui: int):
    """
        tien_goc: so tien gui
        lai_suat: percentage (eg: 0.037)
        ky_han (thang)
        thoi_gian_gui (thang)
    """
    if thoi_gian_gui < ky_han:
        return tien_goc

    return tien_goc*(1 + lai_suat*ky_han/12)**(thoi_gian_gui/ky_han)


TIEN_GOC = 60
TOTAL_MONTHS = 36
THOI_GIAN_GUI = range(1, TOTAL_MONTHS + 1)

fig, ax = plt.subplots()

for item in lai_suat_theo_ky_han:
    label = f"Kỳ hạn: {item['ky_han']
                       } thang ({round(item['lai_suat']*100, 2)}%)"

    danh_sach_lai_kep = []
    for thoi_gian_gui in THOI_GIAN_GUI:
        lai_kep = tinh_lai_kep(
            TIEN_GOC,
            item["lai_suat"],
            item["ky_han"],
            thoi_gian_gui
        )

        danh_sach_lai_kep.append(round(lai_kep, 2))

    print(label)
    print(danh_sach_lai_kep)

    ax.plot(THOI_GIAN_GUI, danh_sach_lai_kep, label=label)

ax.legend()
ax.set_xlabel('Thời gian gửi')
ax.set_ylabel('Số tiền lãi')


plt.xticks(range(TOTAL_MONTHS + 1))
plt.show()