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Welcome back.

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So let's go over some questions
that use dictionary accumulation.

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In this question we're provided a string,
sentence.

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And the question asks us to split the
string into a list of words, and then to

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create a dictionary that contains each
word and the number of times it occurs.

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And that dictionary should
be named word_counts.

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So the first thing that I'm going to do

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is I'm going to split
our sentence into words.

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We can do that by calling
the split method on string.

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I'll say words = sentence.split().

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And so
words is going to be a list of strings.

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The first item is going to be The.

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The 2nd item is going to be dog.

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The 3rd item is going to be chased,
and so on.

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So then we want to use
dictionary accumulation.

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And in this question we’re told to
use the dictionary word_counts.

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So I’m going to name my
accumulator variable word_counts.

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And I’m going to initialize
it as an empty dictionary.

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Then, we need to loop
through all of the words.

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So I'll say for every word in words.

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And we want to say,
if that word isn't in our dictionary so

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far, so if word is not in word_counts.

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And if it's not there we
initialize its value to 0,

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so word_counts[word] = 0.

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And then still inside of our for loop,
but outside of the if statement,

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we're going to increment
the value of word_counts[word].

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So word_counts[word] =
word_counts[word] + 1.

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So let's run our code, and we can see
that it produces the correct value.

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If I actually print out
the value of word_counts.

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So if I say print(word_counts).

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Then we can see that the word 'The'
with a capital T appeared one time.

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The word 'the' with a lowercase
t appeared three times.

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'Into' appeared once.

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'Rabbit' appeared twice, and so on.

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In this question we're asked to create
a dictionary called char_d from

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the string stri, so
that the key is a character and

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its value is how many times
that character occurred.

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So this is again a straightforward
application of the dictionary

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accumulation pattern.

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So I'm going to name my
dictionary accumulator char_d.

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Then I loop through
every character in stri.

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So I'll say for c in stri.

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And if I haven't seen
that character before,

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so if c is not in char_d
then char_d[c] = 0.

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And then inside of the for,
but outside of the if,

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I say char_d[c] = its previous value.

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+ 1.

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So when I run my code then I can
see that it worked correctly.

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But let me run this code in CodeLens,
just to see again what's going on here.

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So on line 1 we initialize stri
to be the string "what can I do".

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On line 3 we initialize our accumulator
variable, our accumulator dictionary,

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to be an empty dictionary.

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Then we loop through
every character in stri.

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So we first say, c is the character "w",
or the first character.

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And then we say if c is not in char_d,
which it is not, so

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we assign char_d[c] or char_d[w] to be 0,
and then we increment it.

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Same thing with the letter "h".

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So "h" isn't in our dictionary,
so we're going to add it, and

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initialize its value to 1.

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Same thing with "a".

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The character "a" was not in our
dictionary so we initialize it to 1.

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Same thing with "t".

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Same thing with the character " ".

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And "c".

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So at this point we're at this "a".

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And we're going to see that
"a" is in our dictionary.

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We're going to skip this if, and

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we're going to say char_d[a]
= its previous value + 1.

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So we'll see this update to be 2.

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And then we keep adding
characters as we go on.

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The second time we get to a space.

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So at this point we're at this space.

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Then we'll see this value increment by 1,
and so on.

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That's all for now, until next time.