"ERR 7"
A ticket machine shows: "ERR 7". You do not know what is wrong. You press buttons. You miss your train.
Another machine shows: "Please put in 2 pounds 50." You know what to do.
Both machines work. Only one is easy to use. The brief says the desk staff are not technical, so your tool must be like the second machine.
Key words
| Word | What it means | Example |
|---|---|---|
| User experience | How easy and nice a tool is to use. | clear messages, simple menus |
| Prompt | A message that tells the user what to type. | Type the hour, from 9 to 20 |
| Error message | A message that says something went wrong, and how to fix it. | There is no court 3. Choose 1 or 2. |
| Consistent | The same words and the same look every time. | always "Cancel", never "Remove" |
| Menu | A numbered list of choices. | 1. Book a court |
| Default | The value used when the user types nothing. | member: yes |
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A good error message has three parts
| Part | What it says | Example |
|---|---|---|
| What happened | The problem, in plain words | The hour 21 is not allowed. |
| Why | The rule behind it | The club closes at 9 in the evening. |
| What to do | The next step | Please choose an hour from 9 to 20. |
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Try it: say a result well
price = 8
hours = 2
print(price)
print("The price for", hours, "hours is", "{:.2f}".format(price), "pounds.")
answer = " YES "
print(answer.strip().lower() == "yes")
# {:.2f} shows 2 numbers after the point (8 becomes 8.00).
# strip() removes spaces. lower() makes small letters.
# Change the price to 4.5 and run it again.
Quick check: messages
Have a go
Quick check: messages
4 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Say the same thing the same way
A user learns your tool by using it. Help them.
Use the same word for the same thing. If one screen says "Book" and another says "Reserve", the user wonders if they are different.
Put buttons in the same place. Write prices the same way each time: 8.00 pounds.
Inconsistent and consistent
| Inconsistent | Consistent |
|---|---|
| Book, Reserve and Make booking | Book everywhere |
| Prices as 8, 8.0 and 8 pounds | 8.00 pounds everywhere |
| Some errors in red, some plain | Every error starts with "Sorry" and says what to do |
| Hours typed as 10, ten and 10:00 | Always a number from 9 to 20 |
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