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192. Word Frequency
192. Word Frequency
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Write a bash script to calculate the frequency of each word in a text file words.txt
.
For simplicity sake, you may assume:
words.txt
contains only lowercase characters and space‘ ‘
characters.- Each word must consist of lowercase characters only.
- Words are separated by one or more whitespace characters.
For example, assume that words.txt
has the following content:
the day is sunny the thethe sunny is isYour script should output the following, sorted by descending frequency:
the 4is 3sunny 2day 1
Note:
Don‘t worry about handling ties, it is guaranteed that each word‘s frequency count is unique.
思路:统计所有词放入llist,通过集合去重,根据set里面的关键字查每个单词频率
注意:读取txt文件行尾要去除/n
myset=setlist( mylist = list(set)
list.count(optt统计list中opt对象的重复次数
import oslist1 = []f = open(‘words.txt‘,‘r‘)lines = f.readlines()for eachline in lines: list1 += eachline.split()list2 = list(set(list1))dict = {}for i in range(len(list2)): word = list2[i] num = list1.count(word) dict[word] = numprint dict
列表类型内建函数 List Method Operation
list.append(obj) 向列表中添加一个对象 obj
list.count(obj) 返回一个对象 obj 在列表中出现的次数
list.extend(seq)a 把序列 seq 的内容添加到列表中
list.index(obj, i=0, j=len(list)) 返回 list[k] == obj 的 k 值,并且 k 的范围在 i<=k<j;否则 引发 ValueError 异常.
list.insert(index, obj) 在索引量为 index 的位置插入对象 obj.
list.pop(index=-1)a 删除并返回指定位置的对象,默认是最后一个对象
list.remove(obj) 从列表中删除对象 obj
list.reverse() 原地翻转列表
list.sort(func=None,key=None,reverse=False)以指定的方式排序列表中的成员,如果 func 和 key 参数指定, 则按照指定的方式比较各个元素,如果 reverse 标志被置为 True,则列表以反序排列.
myset = set(list)
mylist = list(set)
创建set
>>> s1
=
set
(
"qiwsir"
)
#把str中的字符拆解开,形成set.特别注意观察:qiwsir中有两个i
>>> s1
#但是在s1中,只有一个i,也就是不能重复
set
([
‘q‘
,
‘i‘
,
‘s‘
,
‘r‘
,
‘w‘
])
>>> s2
=
set
([
123
,
"google"
,
"face"
,
"book"
,
"facebook"
,
"book"
])
#通过list创建set.不能有重复,元素可以是int/str
>>> s2
set
([
‘facebook‘
,
123
,
‘google‘
,
‘book‘
,
‘face‘
])
#元素顺序排列不是按照指定顺序
>>> s3
=
{
"facebook"
,
123
}
#通过{}直接创建
>>> s3
)
s3
=
{
"facebook"
,
123
}
#通过{}直接创建
192. Word Frequency