python如何统计字符串中字符的个数

str_= "32Ss8nWn012"
str_count = 0
# 字符串本身就是迭代器
for s in str_:
    if s.isalpha():
        str_count += 1
# 输出计数器
print(str_count)

import string

str_ = "32Ss8nWn012"
str_count = 0
str_ = str_.lower()
# 遍历ascii码中的小写英文字母
for i in string.ascii_lowercase:
    # 内置函数count效率高
    str_count += str_.count(i)

print(str_count)

import re

str_ = "32Ss8nWn012"
# [a-zA-Z]是匹配内容，str_是待匹配的对象
str_ = re.findall('[a-zA-Z]',str_)
print(len(str_))

alist=['l','am','a','student']
#先将列表转化为字符串
str=""
for i in alist:
    str+=i 
#统计无重复的字符    
list=set(str)
print(list)       
#利用count统计
li=[]
for j in list:
    num=str.count(j)
    #print(j)
    print(num)
    li.append(num)
print(li)
#让元素的个数与元素一一对应
log3 = dict(zip(list,li))
print(log3)

# 统计一行字符的不同字符个数
str = input("请输入一行字符：")
count1 = count2 = count3 = 0
for s in str:
if "a" <= s <= "z" or "A" <= s <= "Z":
count1 += 1 # 英文计数
elif 0x4e00 <= ord(s) <= 0x9fa5: # 中文的Unicode编码范围
count2 += 1 # 中文计数
elif 48 <= ord(s) and ord(s) <= 57:
count3 += 1 # 数字计数
print("该行字符有空格{0}个".format(str.count(" "))) # 统计空格
print("该行字符有英文字符{0}个".format(count1)) # 计数统计，统计英文字符
print("该行字符有中文字符{0}个".format(count2)) # 计数统计，统计中文字符
print("该行字符有数字{0}个".format(count3)) # 计数统计，统计数字字符
print("该行字符有其他字符{0}个".format(len(str)-count1-count2-count3-str.count(" "))) # 统计其他字符