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Test your basic knowledge |
Perl Programming
Start Test
Study First
Subject
:
it-skills
Instructions:
Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can
study here
.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.
This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Returns the sub string starting at index $startindex and ending after $numchars chars in the string $string
substr($string, $startindex, $numchars)
size string comparison operators
Expression Quantifiers
delete($hashName{key})
2. Removes the first element of the array shift
@entireFile=<FILEHANDLE>
(@array)
chomp($string)
values(%hash)
3. The _______ in perl: - used to execute an external command - will output results of command to terminal - returns the exit status of the program that ran - use this for commands that you dont care about SAVING the output to a variable
sort(@array)
similar data types
system() function
like functions
4. Add a new element to the from of the array with the value $newwValue
unshift(@array, $newValue)
system() function
Hash variables
interpreter
5. < - > - == - <= - >= - !=
basic binding operators
comments
arithmetic comparison operators
@arrayName size
6. _________ in perl - Singular variable - starts with "$" - Number or characer or string- Perl does automatic type conversion of these
Scalar variables
access modes
keys(%hash)
%ENV hash array
7. The use of ______ in perl - Documenting code - Created by placing a "#" on a line. - are not multi-line
size string comparison operators
interpreter
comments
substr($string, $startindex, $numchars)
8. Arrays can be assigned or read in _________
like functions
arithmetic comparison operators
scalar context (Ex: $myArray[4] = 2)
similar data types
9. Explain how to read a line from a file handle
push(@array, $newValue)
$line=<FILEHANDLE>
basic binding operators
@ARGV
10. Removes trailing newline
Special array
chomp($string)
reverse(@array)
command substitution
11. Returns a copy of the string with the first letter upper case
FILEHANDLE
ucfirst($string)
Hash variables
push(@array, $newValue)
12. Returns the length of the string including escape sequences
chomp($string)
length($string)
reverse(%hashName)
reverse(@array)
13. Common ________: keys(%hash) - values(%hash) - each(%hash) - delete($hash{keyName}) - exists($hash{keyName}) - reverse(%hash)
hash functions
Variable context
(@array)
foreach
14. Stores information about the current users environment. You can print this from the command line using printenv
%ENV hash array
interpreter
chomp(@string)
keys(%hash)
15. _________ $#arrayName give value of last index available in the array. Ex an array of size 5 will have its $#arrayName = 4
use moduleName; Ex: use Roman;
scalar
Special array
system() function
16. The two primary methods of executing _______ in perl: - system("command args") - - `command args`
FILEHANDLE
last index
chomp($string)
system commands
17. To get rid of the ________ in $line you could now chomp() (Ex: chomp($line);)
Scalar variables
substr($string, $startindex, $numchars)
values(%hash)
newline
18. The four types of loops in perl: while - until - for - ________
unshift(@array, $newValue)
string manipulation functions
foreach
(@array)
19. Returns all of the keys of the hash as an array
keys(%hash)
(@array)
newline
Hash variables
20. ________ in perl - can be scalar array or hash context - tells the interpreter what you are looking for (Ex: "$arrayname[$index_number]")
Variable context
Hash variables
use moduleName; Ex: use Roman;
access modes
21. Two ____________ in regular expressions: =~ Contains - !~ Does not contain
unshift(@array, $newValue)
command substitution
basic binding operators
Editing
22. scalar(@arrayName) returns the ______ of the array names
values(%hash)
use moduleName; Ex: use Roman;
push(@array, $newValue)
@arrayName size
23. Returns a two element ray of the next key value pair; resultArray[0] is the key resultArray[1] is the value
each(%hash)
flow-control
$hashName{keyName}="Value to Add"
size string comparison operators
24. Common ___________: substr($string, $start, $numchars); - length($string) - lc($string) - uc($string) - chomp($string) - chomp(@string) - join(':", @string) - split(/\s/, $string) - lcfirst($string) - ucfirst($string)
lcfirst($string)
string manipulation functions
lc($string)
Expression character classes
25. To write to a filehandle
system commands
print(FILEHANDLE "Data to outputn");
chomp(@string)
command substitution
26. The three basic ________ of the open() function: > write - >> append - < read file
command substitution
hash functions
access modes
@ARGV
27. Removes the last element from the array pop
basic binding operators
newline
(@array)
keys(%hash)
28. To include modules in perl
flow-control
use moduleName; Ex: use Roman;
chomp($string)
keys(%hash)
29. The two phases of creating a PERL program _______ - Execution
Editing
reverse(%hashName)
basic binding operators
substr($string, $startindex, $numchars)
30. A special system variable used to pass arguments to script
print(FILEHANDLE "Data to outputn");
@ARGV
execution block
like functions
31. _________ of scalar variables in perl - using "=" - Ex: $myVariable = 5;
chomp(@string)
Assignment
foreach
Array variables
32. Regular __________: * - 0 or more characters - + - 1 or more characters - ? - 0 or 1 characters
Assignment
unshift(@array, $newValue)
Expression Quantifiers
lc($string)
33. Sort and array alphabetically
comments
scalar context (Ex: $myArray[4] = 2)
sort(@array)
Special array
34. Assignment of a hash variable for a single hash element
last index
$hashName{keyName}="Value to Add"
command substitution
reverse(%hashName)
35. Assignment of hash variables in perl (when oringally defining the hash)
join(':', @array)
%hashname = (key1=>"value1", key2=>"value2", key3=>"Value3")
comments
newline
36. Common ________: pop(@array) - push(@array, $new Value) - shift(@array) - unshift(@array, $newValue) - sort(@array) - reverse(@array)
lcfirst($string)
Assignment
length($string)
array functions
37. Does the hash key with "keyName" exists
access modes
push(@array, $newValue)
newline
exists($hashName{keyName})
38. Returns a copy of the string as all lower case
last index
chomp(@string)
lc($string)
uc($string)
39. The open() statement in perl: open(________, file_mode, "filename.txt")
split(/\s/, $string)
exists($hashName{keyName})
FILEHANDLE
system() function
40. Returns a copy of the string as all upper case
command substitution
use moduleName; Ex: use Roman;
Assignment
uc($string)
41. Modules in perl - Synonymous with header files in C - Collection of ______ and variables that may be used in your program
print(FILEHANDLE "Data to outputn");
like functions
$line=<FILEHANDLE>
Editing
42. ________ in perl - A collection of data (static data or scalar variables or arrays or hashes can all be stored in an array element)
length($string)
%ENV hash array
delete($hashName{key})
Array variables
43. The use of "if" "if-else" and "if-elsif-else"
flow-control
%ENV hash array
Hash variables
chomp(@string)
44. _________ @arrayName) returns the size of the array
newline
access modes
$line=<FILEHANDLE>
scalar
45. $#arrayName returns the value of the ______ of the array (NOT the data stored in that array element)
lcfirst($string)
Special array
last index
scalar context (Ex: $myArray[4] = 2)
46. The __________ in perl: - uses grave marks `command args`- returns the output of the command to the variable you specify - if $output = `command arg` the output is stored all in one variable (all lines seperated by n) - if @output = `command arg` the
ucfirst($string)
command substitution
flow-control
string manipulation functions
47. Remove trailing newline from each element in the array
size string comparison operators
sort(@array)
chomp(@string)
Assignment
48. Delete the hash entry with the key given
delete($hashName{key})
Expression Quantifiers
unshift(@array, $newValue)
arithmetic comparison operators
49. In perl the _______ will recognize syntax errors and halt execution BEFORE it begins - and will output statements; it does not understand and the line which it encountered the error on
hash functions
%hashname = (key1=>"value1", key2=>"value2", key3=>"Value3")
Expression Quantifiers
interpreter
50. Swap keys for values and values for keys. Will cause issues if there are multiple hash entries with the same value
reverse(%hashName)
use moduleName; Ex: use Roman;
size string comparison operators
$hashName{keyName}="Value to Add"