人気のFunction

import cv2
from PIL import Image, ImageDraw, ImageFont 
import numpy as np

def pil2cv(image):
    ''' PIL型 -> OpenCV型 '''
    new_image = np.array(image, dtype=np.uint8)
    if new_image.ndim == 2:  # モノクロ
        pass
    elif new_image.shape[2] == 3:  # カラー
        new_image = cv2.cvtColor(new_image, cv2.COLOR_RGB2BGR)
    elif new_image.shape[2] == 4:  # 透過
        new_image = cv2.cvtColor(new_image, cv2.COLOR_RGBA2BGRA)
    return new_image

def count_characters(s):
    count = {}
    for char in s:
        count[char] = count.get(char, 0) + 1
    return count

import cv2
from PIL import Image, ImageDraw, ImageFont 
import numpy as np

def cv2pil(image):
    ''' OpenCV型 -> PIL型 '''
    new_image = image.copy()
    if new_image.ndim == 2:  # モノクロ
        pass
    elif new_image.shape[2] == 3:  # カラー
        new_image = cv2.cvtColor(new_image, cv2.COLOR_BGR2RGB)
    elif new_image.shape[2] == 4:  # 透過
        new_image = cv2.cvtColor(new_image, cv2.COLOR_BGRA2RGBA)
    new_image = Image.fromarray(new_image)
    return new_image

import re

def is_valid_email(email):
    pattern = r"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$"
    return re.match(pattern, email) is not None

def fibonacci(n):
    if n <= 1:
        return n
    else:
        return fibonacci(n-1) + fibonacci(n-2)

from datetime import datetime

def days_between_dates(date1, date2):
    d1 = datetime.strptime(date1, "%Y-%m-%d")
    d2 = datetime.strptime(date2, "%Y-%m-%d")
    return abs((d2 - d1).days)