20170417学习find、replace、abs三个函数

search = ‘168‘
num_a = ‘1386-168-0006‘
num_b = ‘1681-222-0006‘
print(search + ‘ is at ‘ + str(num_a.find(search)) + ‘ to ‘ + str(num_a.find(search) + len(search)) + ‘ of num_a‘)

• old：将被替换的子字符串
• new：新字符串，用于替换old子字符串
• max: 可选字符串, 替换不超过 max 次
• print str.replace("is", "was", 3);

def text_filter(word,censored_word = ‘lame‘,changed_word = ‘Awesome‘):
    return word.replace(censored_word,changed_word)
print(text_filter(‘Python is lame!‘))#实现过滤，lame替换为Awesome

③abs()函数

解释：返回数字的绝对值