String Knowledge

Question 1

Why does this evaluate true?

‘z’ > ‘a’

Why is this false?

‘tb’ < ‘ta’

Answer 1

So strings become NaN when converted to a number. But with some comparisons, JavaScript uses the so-called “dictionary” or “lexicographical” order. It does this letter by letter (sort of like a number).
so z has a higher number than a

tb has a higher number than ta

Question 2

“hello my name is stringy the whooping string”
but we want a function that will capitalize the first letter of each word
“Hello My Name Is Stringy The Whooping String”

Answer 2

With .split(), .map(), charAt(), .toUpperCase() and slice(). join()

Take the string

.split() it

.map() that array taking each word and using charAt(0), toUpperCase() it, and concatentate it with the rest of the word sliced.

Then join it.

OR

.split(), .map(), x[0].toUpperCase + x.subString

Question 3

What happens with this code:

alert( ‘hello ${1}’ );

Answer 3

// hello 1

is alerted in browser

Question 4

Evaluate:

‘Bee’ > ‘Be’

Answer 4

True

Question 5

‘z’ > ‘aaaa’

Answer 5

True

It judges character from left to right. Returns whenever oneis larger than the other. it does not convert all characters into a single value.

Question 6

How does the string > or < algorithm work

Answer 6

Compare the first character of both strings.

If the first character from the first string is greater (or less) than the other string’s, then the first string is greater (or less) than the second. We’re done.

Otherwise, if both strings’ first characters are the same, compare the second characters the same way.

Repeat until the end of either string.

If both strings end at the same length, then they are equal. Otherwise, the longer string is greater.

Question 7

Two benefits of backticks

Answer 7

1. Allow embedded expressions

2. Allow string to span multiple lines

Question 8

escape a backslash

Answer 8

\\

Question 9

Add a tab in a string

Answer 9

\t

Question 10

Add a unicode symbol or character

Answer 10

\xXX Unicode character with the given hexadecimal Unicode XX, e.g. ‘\x7A’ is the same as ‘z’.

\uXXXX A Unicode symbol with the hex code XXXX in UTF-16 encoding, for instance \u00A9 – is a Unicode for the copyright symbol ©. It must be exactly 4 hex digits.

\u{X…XXXXXX} (1 to 6 hex characters) A Unicode symbol with the given UTF-32 encoding. Some rare characters are encoded with two Unicode symbols, taking 4 bytes. This way we can insert long codes.

Question 11

What is alerted:

alert( ‘My\n’.length );

Answer 11

// 3
\n is a single “special” character, so the length is indeed 3.

Question 12

What is str at the end?
let str = 'Hi';
str[0] = 'h';

Answer 12

Hi

strings are immutable

Question 13

What is str at the end?
let str = 'Hi';
str = 'h' + str[1];

Answer 13

hi

the variable is reassigned to something. The string did not change.

Question 14

‘a’ < ‘Z’
‘a’ < ‘b’
‘a’ < ‘A’

Answer 14

false
true
false

Here is the number assigned to each character ascending:
let str = '';

for (let i = 65; i <= 220; i++) {
  str += String.fromCodePoint(i);
}
alert( str );

Gives:
// ABCDEFGHIJKLMNOPQRSTU
VWXYZ[\]^_`abcdefghijklmn
opqrstuvwxyz{|}~€‚ƒ„
 ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉ
ÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜ

Question 15

‘Österreich’ > ‘Zealand’

‘Osterreich’ > ‘Zealand’

Answer 15

true
false

let str = ‘’;

for (let i = 65; i <= 220; i++) {
  str += String.fromCodePoint(i);
}
alert( str );
// ABCDEFGHIJKLMNOPQRSTU
VWXYZ[\]^_`abcdefghijklmn
opqrstuvwxyz{|}~€‚ƒ„
// ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉ
ÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜ

Question 16

Count the number of instances of a substring in a string

Answer 16

myString.match(/substring/g).length