Project: a name tag and a text analyser

What you will be able to do

After this lesson you can

• plan a program that works on text,
• build a neat border from the length of a string,
• count and find things in a sentence, and
• test a text program with a sentence that you can check by hand.

Project 1: a name tag maker

We want a tag that is wide enough for the name and the role, with the text in the middle, like this:

+------------+
|  Asha Rao  |
|  Student   |
+------------+

Plan in words

1. The width of the tag is the length of the longer line, plus a few spaces for the edges.
2. The border is a plus sign, a row of dashes of that width, and a plus sign.
3. Each line of text is centred in that width, between two bars.

The program

Now test the program. Change name = "Asha Rao" to a very long name, such as "Dr Ananya Venkataraman". Does the tag grow to fit it? Change it to a very short name, "Om". Is the tag still neat? A program that works only for one name is not good enough.

center() adds the spaces for you. When the spaces cannot be shared out equally, the extra one goes to one side.

Project 2: a text analyser

A text analyser tells you facts about a sentence. We want to know the number of characters, words and vowels, and also the first word, the sentence in capital letters, and the sentence reversed.

Plan in words

1. Characters: len(text).
2. Words: a sentence has one more word than spaces, if the words are separated by single spaces. So text.count(" ") + 1.
3. Vowels: count each of a, e, i, o, u in the small-letter version, and add the five numbers.
4. The first word: from the start to the position of the first space.
5. Capitals: upper(). Reversed: [::-1].

The program

A word of care. Counting words with count(" ") + 1 fails when the text has two spaces in a row, or spaces at the ends. A good habit: clean the text first with text.strip().

Make it your own

Choose one, and do it without looking at a solution.

1. Tag. Add a third line, such as the class or the city.
2. Tag. Change the border character from - to =, and the corners to *.
3. Analyser. Show the last word of the sentence. Hint: text.rfind(" ") gives the position of the last space.
4. Analyser. Show whether the sentence ends with a full stop.
5. Analyser. Ask the user to type the sentence with input(), and strip() it first.

Common mistakes

• Counting characters by hand instead of with len(). You will count wrong.
• A border that is too short or too long because the width was not computed from the text.
• Counting only small letters. text.count("a") misses A. Use text.lower().count("a").
• Assuming one space between words and not cleaning the text.

Practice

Start with two quick questions. Each New numbers gives you a fresh one, so you can practise as long as you like.

Then the labs and the problems:

1. Warm-up. Do the lab Text detective, if you have not done it.
2. Build. Open the lab Project: the name tag. It gives your program a name and a role and checks the shape of the tag.
3. Stretch. Open the problem Initials, and make the analyser show the initials of a full name.

Remember these

• Plan a text program step by step: the facts, the measures, the result.
• Use len() and max() to make a border fit the text.
• count() and find() answer many questions about a sentence.
• Test with a short text, a long text, and a text that you can check by hand.

Check yourself

Try each one on your own first. If you are stuck, open a hint. Then check with Show the answer.

1. How many words does "red green blue" have, by the rule count(" ") + 1?

2. What does f"{'ab':^6}" show, between square brackets?

3. Why do we use text.lower().count("a") and not text.count("a") to count the letter A?