s1 = 'hello world '

序列的通用操作

print(s1 + 'mia')
print(s1*3)
print(len(s1))
print(max(s1), min(s1))
print(ord('w'))
print(ord(' '))

del s1

print('s' in s1)
print('abcd' < 'abce')
print('cd' < 'abcd')

字符串的遍历

for i in s1:
print(i)
for index,value in enumerate(s1):
print(index,value)
for i in range(len(s1)):
print(i,s1[i])

类型转换

print(str(12), type(str(12))) # int-->str
print(str([1, 2, 3, 4]), type(str([1, 2, 3, 4]))) # list-->str
print(str((1,))), type(str((1,))) # tuple-->str

常用方法

print(s1.islower())
print(s1.isupper())
print(s1.count('0'))
print(s1.strip())
print(s1.split(' ')) # 分隔字符串
print(s1.find('a '))
print('#'.join(['111', '222', '333']))

print(s1. )

字符串的统计

s = input('请输入一篇文章')

字母的个数，数字的个数，符号的个数

a, b, c = 0, 0, 0
for i in s:
if i.isdigit():
b += 1
elif i.isalpha():
a += 1
else:
c += 1
print(a, b, c)