Read .txt file and analyze
I'm working Huffman coding of any .txt file, so first I need to analyse this text file. I need to read it, then analyse. I need "exit" like table:
letter | frequency(how many times same latter repeated) | Huffman code(this will come later)
I started with:
f = open('test.txt', 'r') #open test.tx
for lines in f:
print lines #to ensure if all work...
How can I order reading characters from file in alphabetic order:
with open("test.txt") as f_in:
for line in f_in:
for char in line:
frequencies[char] += 1
???Many thanks
Well I tried like this:
frequencies = collections.defaultdict(int)
with open("test.txt") as f_in:
for line in f_in:
for char in line:
frequencies[char] += 1
frequencies = [(count, char) for char, count in frequencies.iteritems()]
frequenci开发者_如何学Pythones.sort(key=operator.itemgetter(1))
But compiler return me an "error" enter code here
I need this alphabetic order in for loop, not at end at frequencies...
To get your table of frequencies, I would use a defaultdict
. This will only iterate over the data once.
import collections
import operator
frequencies = collections.defaultdict(int)
with open(filename) as f_in:
for line in f_in:
for char in line:
frequencies[char] += 1
frequencies = [(count, char) for char, count in frequencies.iteritems()]
frequencies.sort(key=operator.itemgetter(1))
with open('test.txt') as f: data = f.read()
table = dict((c, data.count(c)) for c in set(data))
I made this solution using a collections.Counter()
:
import re
import collections
if __name__ == '__main__':
is_letter = re.compile('[A-Za-z]')
frequencies = collections.Counter()
with open(r'text.txt') as f_in:
for line in f_in:
for char in line:
if is_letter.match(char):
frequencies[char.lower()] += 1
# Sort characters
characters = [x[0] for x in frequencies.most_common()]
characters.sort()
for c in characters:
print c, '|', str(frequencies[c])
The regular expression is_letter
is used to filter for only the characters we are interested in.
It gives output that looks like this.
a | 177
b | 29
c | 7
d | 167
e | 374
f | 58
g | 100
h | 44
i | 135
j | 21
k | 64
l | 125
m | 85
n | 191
o | 105
p | 34
r | 185
s | 130
t | 146
u | 34
v | 68
x | 1
y | 14
精彩评论