Python 过滤字母和数字实例1实例 2实例 3

crazystring = 'dade142.!0142f[., ]ad'

# 只保留数字
new_crazy = filter(str.isdigit, crazystring)
print(''.join(list(new_crazy)))
# 只保留字母
new_crazy = filter(str.isalpha, crazystring)
print(''.join(list(new_crazy)))


# 只保留字母和数字
new_crazy = filter(str.isalnum, crazystring)
print(''.join(list(new_crazy)))

# 如果想保留数字0-9和小数点’.’ 则需要自定义函数

new_crazy = filter(lambda ch: ch in '0123456789.', crazystring)
print(''.join(list(new_crazy)))

import re
L = ['小明', 'xiaohong', '12', 'adf12', '14']
for i in range(len(L)):
    if re.findall(r'^[^\d]\w+', L[i]):
        print(re.findall(r'^\w+$', L[i])[0])

L = ['xiaohong', '12', 'adf12', '14', '晓明']
for x in L:
    try:
        int(x)
    except:
        print(x)

L = ['xiaohong', '12', 'adf12', '14', '晓明']

# 对于python3来说同样还可以使用string.isnumeric()方法
for x in L:
    if not x.isdigit():
        print(x)
# for x in L:
#     if not x.isnumeric():
#         print(x)

import re
x = 'a12121assa'
x = '1我爱你1'
r1 = '[a-zA-Z0-9’!"#$%&\'()*+,-./:;<=>?@，。?★、…【】《》？“”‘’！[\\]^_`{|}~]+'

print(re.sub(r1, '', x))