Can someone explain how to store and display a line count with user input?

Question

This simple while loop that stops at a sentinel value and otherwise continuously asks for user input.
How would I use the incrementing line count variable to display after on what line the user inputted certain things? I would guess use of a dictionary is needed?

lineCount = 1
d = {} #is this needed?
q = raw_input("enter something")
while q != "no":
    lineCount += 1
    q = raw_input("enter something")
#code here that stores each new input with its respective line and prints what the user inputted on each corresponding line when the loop ends

Many thanks in advance

Answer 1

Using array:

lines = []
def add_line(line):
    lines.append(line)

def print_lines():
    for i in range(len(lines)):
        print "%d: %s" % (i, lines[i])

lineCount = 1
q = raw_input("enter something")
add_line(q)
while q != "no":
    lineCount += 1
    q = raw_input("enter something")
    if q != "no":
        add_line(q)

print_lines()

Answer 2

Exactly like you said, using a dictionary:

d = {}
lineCount = 1
q = raw_input("enter something: ")
while q != "no":
    lineCount += 1
    q = raw_input("enter something: ")
    d[lineCount] = q

Then you could just query your dictionary if you want to know what the user input at a desired line as d[desired_line].

Assuming you have a simple dictionary, such as:

d = {2: 'b', 3: 'c', 4: 'd', 5: 'no', 6: 'c'}

Then if you'd like to print out the lines where a desired word appear you could define a function like so:

def print_lines(my_dict, word):
    lines = [line for line, ww in my_dict.iteritems() if ww == word]
    return lines

You could call this function with your dictionary (d) and the word your looking for, let's say 'c':

print_lines(d, 'c')

Finally, could iterate over the set of words (unique_words using set) you have and print the lines they appear on by calling the previous function:

def print_words(my_dict):
    unique_words = set([word for word in my_dict.itervalues() if word != 'no'])    
    for word in sorted(unique_words):
        print("'{0}' occurs in lines {1}".format(word, print_lines(my_dict, word)))

UPDATE (for sentences instead of single words):

In case you want to work with sentences, rather than single words per line, you'll need to modify your code as follows:

First, you could define a function to handle the user input and build the dictionary:

def build_dict():
    d = {}
    lineCount = 1
    q = raw_input("enter something: ")
    while q != "no":
        d[lineCount] = q        
        lineCount += 1
        q = raw_input("enter something: ")        
    return d

Let's say you build a dictionary like such:

d = {1: 'a x', 2: 'a y', 3: 'b x'}

Then you can define a helper function that tells you at which line a particular word occurs:

def occurs_at(my_dict, word):
    lines = [line for line, words in my_dict.iteritems() if word in words]
    return lines

Finally, you can query this function to see where all your words occur at (and you can decide which words to ignore, e.g. 'a').

def print_words(my_dict, ignored=['a']):
    sentences = [sentences.split(' ') for sentences in my_dict.itervalues()]
    unique_words = set([word for sentence in sentences for word in sentence])
    for word in sorted(unique_words):
        if word not in ignored:
            print("'{0}' occurs in lines {1}".format(word, occurs_at(my_dict, word)))