Introduction: Accumulating Multiple Results In a Dictionary

1. If we want to find out how often the letter ‘t’ occurs, we can accumulate the result in a count variable.

## If we want to find out how often the letter ‘t’ occurs, we can accumulate the result in a count variable.

f = open('scarlet.txt', 'r')
txt = f.read()
# now txt is one long string containing all the characters
t_count = 0 #initialize the accumulator variable
for c in txt:
    if c == 't':
        t_count = t_count + 1   #increment the counter
print("t: " + str(t_count) + " occurrences")

2. We can accumulate counts for more than one character as we traverse the text. Suppose, for example, we wanted to compare the counts of ‘t’ and ‘s’ in the text.

## We can accumulate counts for more than one character as we traverse the text. Suppose, for example, we wanted to compare the counts of ‘t’ and ‘s’ in the text.
f = open('scarlet.txt', 'r')
txt = f.read()
# now txt is one long string containing all the characters
t_count = 0 #initialize the accumulator variable
s_count = 0 # initialize the s counter accumulator as well
for c in txt:
    if c == 't':
        t_count = t_count + 1   #increment the t counter
    elif c == 's':
        s_count = s_count + 1
print("t: " + str(t_count) + " occurrences")
print("s: " + str(s_count) + " occurrences")

3. All Letter Counts

f = open('scarlet.txt', 'r')
txt = f.read()
# now txt is one long string containing all the characters
letter_counts = {} # start with an empty dictionary
for c in txt:
    if c not in letter_counts:
        # we have not seen this character before, so initialize a counter for it
        letter_counts[c] = 0

    #whether we've seen it before or not, increment its counter
    letter_counts[c] = letter_counts[c] + 1

for c in letter_counts.keys():
    print(c + ": " + str(letter_counts[c]) + " occurrences")

4. Provided is a string saved to the variable name sentence. Split the string into a list of words, then create a dictionary that contains each word and the number of times it occurs. Save this dictionary to the variable name word_counts.

## Provided is a string saved to the variable name sentence. Split the string into a list of words, then create a dictionary that contains each word and the number of times it occurs. Save this dictionary to the variable name word_counts.