如何利用python提取字符串中的数字

dream = "123456"
print(dream.isdigit())
# 返回：True

dream = "123abc456"
print(dream.isdigit())
# 返回：False

dream = 'abcd'
print(dream.isdigit())
# 返回：False

filter(function, iterable)

def is_odd(n):
    return n % 2 == 1
 
tmplist = filter(is_odd, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
newlist = list(tmplist)
print(newlist)

l = [x for x in range(10)]
print(list(filter(lambda x : x%2 == 0, l)))

import math
def is_sqr(x):
    return math.sqrt(x) % 1 == 0
 
tmplist = filter(is_sqr, range(1, 101))
newlist = list(tmplist)
print(newlist)

L = range(1, 101)

def isprimer(n):
    flag = 1
    for i in range(2, n):
        if n % i == 0:
            flag = 0
    if flag == 0:
        return n

print(list(filter(isprimer, L)))

def not_empty(s):
  return s and s.strip()

filter(not_empty, ['A', '', 'B', None, 'C', ' '])

def _odd_iter():
    n = 1
    while True:
        n = n + 2
        yield n
        
def _not_divisible(n): 
    return lambda x : x%n>0
 
def primes():
    yield 2
    it = _odd_iter()
    ftr = filter(_not_divisible(2), it) #1
    while True:
        n = next(ftr )        #2
        yield n                
        ftr = filter(_not_divisible(n), ftr ) #3
        
for n in primes():
    if n < 100:
        print('now:',n)
    else:
        break

number = ['12', '333', '4']
number_ = "".join(number)    # 列表转字符串
print(number_)    # 123334

a = "".join(list(filter(str.isdigit, '123ab45')))
print(a)
# 返回12345

b = list(filter(str.isdigit, '123ab45'))
print(b)
# 返回['1', '2', '3', '4', '5']

time_ = "2019年09月04日 11:00"
time_filter = filter(str.isdigit, time_)

print(time_filter)           # <filter object at 0x0000019358731BE0>
print(type(time_filter))     # <class 'filter'>
time_list = list(time_filter)       # ['2', '0', '1', '9', '0', '9', '0', '4', '1', '1', '0', '0']
time_str = "".join(time_list)       # 转为str    201909041100
time_int = int(time_str)            # 转为int    201909041100

import re
str_ = "12今天333天气4不错"
number = re.findall("\d+",str_)    # 输出结果为列表
print(number)
 
# 输出结果：['12', '333', '4']

# 匹配“calibration=”后面的数字
pattern = re.compile(r'(?<=calibration=)\d+\.?\d*')
pattern.findall(string)

# ['0.9863265752792358']

string = "WARNING:tensorflow: 20181011 15:28:39 Initialize training"
pattern = re.compile(r'\d{2}:\d{2}:\d{2}')
pattern.findall(string)
# ['15:28:39']

string = "WARNING:tensorflow: 20181011 15:28:39 Initialize training"
pattern = re.compile(r'\d{4}\d{2}\d{2}\s\d{2}:\d{2}:\d{2}')
pattern.findall(string)
# ['20181011 15:28:39']