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Oct 1st, 2009

-1

Help with loop

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Hi everyone,

I'm working on a homework assignment and i'm brand new to python (i'm a better c++ coder). Anyway, I've used help from classmates and google to compile this code chunk and i need to know how i can make this into a loop so i dont have 26 code chunks.

This code chunks reads a bunch of text from a file and looks at each word and determines fi it begins with 'x' letter (a or b...etc) and then prints out its frequency.

So basically i'm looking for the number of words, in the text, that begin with this letter and that letter.

Thanks for your help!

Python Syntax (Toggle Plain Text)
import sys
result = []
f = open("sample_text.txt")
for line in f:
	for word in line.split():
		if word.startswith('a'):
			result.append(word)
result_length = len(set(result))
print "\nTotal DISTINCT words starting with 'a': ", result_length
 
import sys
result = []
f = open("sample_text.txt")
for line in f:
	for word in line.split():
		if word.startswith('b'):
			result.append(word)
result_length = len(set(result))
print "Total DISTINCT words starting with 'b': ", result_length
import sys
result = []
f = open("sample_text.txt")
for line in f:
	for word in line.split():
		if word.startswith('a'):
			result.append(word)
result_length = len(set(result))
print "\nTotal DISTINCT words starting with 'a': ", result_length

import sys
result = []
f = open("sample_text.txt")
for line in f:
	for word in line.split():
		if word.startswith('b'):
			result.append(word)
result_length = len(set(result))
print "Total DISTINCT words starting with 'b': ", result_length

On down too 'Z'...

Python Syntax (Toggle Plain Text)
import sys
result = []
f = open("sample_text.txt")
for line in f:
	for word in line.split():
		if word.startswith('z'):
			result.append(word)
result_length = len(set(result))
print "Total DISTINCT words starting with 'z': ", result_length
import sys
result = []
f = open("sample_text.txt")
for line in f:
	for word in line.split():
		if word.startswith('z'):
			result.append(word)
result_length = len(set(result))
print "Total DISTINCT words starting with 'z': ", result_length

I have this down 26 times - but obviously that just doesn't work and is bad coding. Any help is greatly appreciated!

Thanks!

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walker164

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Oct 1st, 2009

Re: Help with loop

indentations is 4 spaces,it work with 2 and 8 but never ever us anything else than 4.

A simple fix move line 8 so it get input from loop.
Remove set

Python Syntax (Toggle Plain Text)
import sys
result = []
f = open("sample_text.txt")
for line in f:
	for word in line.split():
		if word.startswith('h'):
			result.append(word)
                        result_length = len(result)
print "Total DISTINCT words starting with 'z': ", result_length
import sys
result = []
f = open("sample_text.txt")
for line in f:
	for word in line.split():
		if word.startswith('h'):
			result.append(word)
                        result_length = len(result)
print "Total DISTINCT words starting with 'z': ", result_length

Here is the script with right indent,and som print to see what happends.

my sample_text.txt

(Toggle Plain Text)

hi this is an test.
hi again why not.
hi number 3.

Python Syntax (Toggle Plain Text)
result = []
f = open("sample_text.txt")
for line in f:
    for word in line.split():
        if word.startswith('h'):
            result.append(word)            
            print result  # use print as help easier to see what happends
            print len(result)  # use  print as help easier to see what happends      
print "Total DISTINCT words starting with '%s' is %d" % (result[0][0], len(result)) 
 
'''
my output-->
['hi']
1
['hi', 'hi']
2
['hi', 'hi', 'hi']
3
Total DISTINCT words starting with 'h' is 3
'''
result = []
f = open("sample_text.txt")
for line in f:
    for word in line.split():
        if word.startswith('h'):
            result.append(word)            
            print result  # use print as help easier to see what happends
            print len(result)  # use  print as help easier to see what happends      
print "Total DISTINCT words starting with '%s' is %d" % (result[0][0], len(result)) 

'''
my output-->
['hi']
1
['hi', 'hi']
2
['hi', 'hi', 'hi']
3
Total DISTINCT words starting with 'h' is 3
'''

Last edited by snippsat; Oct 1st, 2009 at 11:18 pm.

snippsat

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Oct 1st, 2009

Re: Help with loop

Excellent! Thanks!

But is there any way to incorporate the whole alphabet into the

Python Syntax (Toggle Plain Text)
if word.startswith('x')
if word.startswith('x')

(replacing the spot of x with a-z) statement so i dont have to have 26 separate statements? Because i need to find the number of words that begin with every letter.

How would i incorporate that?

walker164

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Oct 2nd, 2009

Re: Help with loop

A dictionary with the letter as the key is the straight forward way to do this. Otherwise use a function with a for loop to pass the letter and the string to the function.

Python Syntax (Toggle Plain Text)
import string
 
letter_dict = {}
for letter in string.ascii_uppercase:
    letter_dict[letter] = 0
 
f = [ "abc def\n",
      "ghi abc def\n",
      "mno stuvw abc\n" ]
 
for line in f:
   for word in line.strip().split():
      letter = word[0].upper()
      letter_dict[letter] += 1
 
for letter in string.ascii_uppercase:
    print "letter %s = %d" % (letter, letter_dict[letter])
import string

letter_dict = {}
for letter in string.ascii_uppercase:
    letter_dict[letter] = 0

f = [ "abc def\n",
      "ghi abc def\n",
      "mno stuvw abc\n" ]

for line in f:
   for word in line.strip().split():
      letter = word[0].upper()
      letter_dict[letter] += 1

for letter in string.ascii_uppercase:
    print "letter %s = %d" % (letter, letter_dict[letter])

Last edited by woooee; Oct 2nd, 2009 at 12:46 am.

woooee

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Oct 2nd, 2009

Re: Help with loop

Thanks buddy!

That is some code i would have never been able to write in 10 years. Very nice. Thanks so much for your help

walker164

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