python统计字符串里每个字符的次数

dd="ewq4aewtaSDDSFDTFDSWQrtewtyufashas"
 print {i:dd.count(i) for i in dd}

import collections
dd="ewq4aewtaSDDSFDTFDSWQrtewtyufashas"
obj = collections.Counter(dd)
print obj

dd="ewq4aewtaSDDSFDTFDSWQrtewtyufashas"
for i in set(dd):
    print(i,dd.count(i))

dd = ‘ewq4aewtaSDDSFDTFDSWQrtewtyufashas‘ 
d = {} 
for c in dd: 
    d[c] = (d[c] + 1) if (c in d) else (1) 
print d

dd="ewq4aewtaSDDSFDTFDSWQrtewtyufashas"
obj = collections.Counter(dd)
print obj.most_common(3)

f = file("data.txt")
s = f.read()
# 这里的s采用文件的方式读取
global list_all
global list_to_statistic
def tran_s_to_list(s):
list_all = []
l = len(s)
# 得到长度，遍历
for x in xrange(0,l):
# 当x不在list中，即第一次出现，追加到list中
if not s[x] in list_all:
list_all.append(s[x])
return list_all

def statistic(s, list_all, list_to_statistic):
l = len(s)
for x in xrange(0,l):
遍历字符串，找到每一个char在list中的index，在list_statistic相应位置加一
list_to_statistic[list_all.index(s[x])] = list_to_statistic[list_all.index(s[x])]+1
# print list_all.index(s[x]),
# print

list_all = tran_s_to_list(s)
# 复制一个和list等长的数组list_statistic，并且全部赋值为0
list_to_statistic = list_all[ : ]
for x in xrange( 0, len(list_all) ):
list_to_statistic[x] = 0

statistic(s, list_all, list_to_statistic);
# 打印
listlength = len(list_all)
for x in xrange(0, listlength):
print str(list_all[x])+"" + "---appers---"+str(list_to_statistic[x])+"---times"