Introduction to Data - Multiple Choice Quiz (answers)"
Last updated on 2023-04-24 | Edit this page
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Overview
Questions
- What does
Fr[ea]nc[eh]
match?
Objectives
- Test knowledge of use of regular expressions in searches
Library Carpentry Week One: Introduction to Data
Exercise Answers
What does Fr[ea]nc[eh]
match?
- this matches
France
,French
,Frence
, andFranch
. It would find words where there were characters either side of these soFrancer
,foobarFrench
, orFranch911
.
What does Fr[ea]nc[eh]$
match?
- this matches
France
,French
,Frence
, andFranch
at the end of a line. It would find words where there were characters before these sofoobarFrench
.
What would match the strings French
and
France
only that appear at the beginning of a line?
-
^France|^French
This would also find words where there were characters afterFrench
such asFrenchness
.
How do you match the whole words colour
and
color
(case insensitive)?
- In real life, you should only come across the case
insensitive variations
colour
,color
,Colour
,Color
,COLOUR
, andCOLOR
(rather than, say,coLour
. So one option would be\b[Cc]olou?r\b|\bCOLOU?R\b
. This can, however, get quickly quite complex. An option we’ve not discussed is to take advantage of the/
delimiters and add an ignore case flag: so/colou?r/i
will match all case insensitive variants ofcolour
andcolor
.
How would you find the whole-word headrest
and or the
2-gram head rest
but not head rest
(that is,
with two spaces between head
and rest
?
-
\bhead ?rest\b
. Note that although\bhead\s?rest\b
does work, it would also match zero or one tabs or newline characters betweenhead
andrest
. In most real world cases it should, however, be fine :)
How would you find a 4 letter word that ends a string and is preceded by at least one zero?
0+[a-z]{4}\b
How do you match any 4 digit string anywhere?
-
\d{4}
. Note this will match 4 digit strings only but will find them within longer strings of numbers.
How would you match the date format dd-MM-yyyy
?
-
\b\d{2}-\d{2}-\d{4}\b
In most real world situations, you are likely to want word bounding here (but it may depend on your data).
How would you match the date format dd-MM-yyyy
or
dd-MM-yy
at the end of a string only?
\d{2}-\d{2}-\d{2,4}$
How would you match publication formats such as
British Library : London, 2015
and
Manchester University Press: Manchester, 1999
?
-
.* : .*, \d{4}
You will find that this matches any text you put beforeBritish
orManchester
. In this case, this regular expression does a good job on the first look up and may be need to be refined on a second depending on your real world application.
Multiple Choice Quiz Answers
- Q1. C
- Q2. A
- Q3. B
- Q4. B
- Q5. C
- Q6. B
- Q7. C
- Q8. A
- Q9. C
- Q10. A
- Q11. B
- Q12. A
Key Points
- Regular expressions answer sheet