Introduction to strings

Introduction to Julia

James Fulton

Climate informatics researcher

Strings

# Strings are surrounded by " "
name = "Jane" # Cannot use 'Jane'


# Strings can be any length
book = "It is a truth universally acknowledged, ..."


println(name)

println(book)

Jane

It is a truth universally acknowledged, ...

Triple quotes

# Triple quotes 
poem = """Beware the Jabberwock, my son!

      The jaws that bite, the claws that catch!"""


println(poem)

Beware the Jabberwock, my son!

The jaws that bite, the claws that catch!

Triple quotes

greeting = """ " Well hello there " """

println(greeting)

 " Well hello there "

greeting = " " Well hello there " "

ERROR: syntax: ...

Concatenating strings

name = "James"

greeting = "Well hello there, "


# Concatenate two strings

println(greeting*name)

Well hello there, James

String interpolation

name = "James"


# Interpolate with $ symbol
greeting = "Well hello there, $name"


println(greeting)

Well hello there, James

String interpolation

x_int = 10


# Insert integer into string
println("The value is $x_int")

The value is 10

x_float = 1.0


# Insert float into string
println("The value is $x_float")

The value is 1.0

x_bool = true


# Insert boolean into string
println("The value is $x_bool")

The value is true

x_char = 'A'


# Insert character into string
println("The value is $x_char")

The value is A

String interpolation

x = 10
y = 3


# Insert x*y into string
println("The product of x and y is $(x*y)")

The product of x and y is 30

String interpolation

x = 10
y = 3


# Insert x*y into string
println("The product of x and y is \$(x*y)")

The product of x and y is $(x*y)

Indexing strings

# Customer's seat
seat = "E5"


# Select character
row = seat[1]       # this returns 'E'



println(row)

println(typeof(row))

E

Char

Indexing strings

# Customer's seat
seat = "E5"

# Select characters
row = seat[1]       # this returns 'E'
number = seat[2]    # this returns '5'


println("Your seat is in row $row, seat number $number.")

Your seat is in row E, seat number 5.

Indexing strings

# Customer's seat
seat = "E5"

# Select characters
row = seat[1]       # this returns 'E'
number = seat[end]  # this returns '5'

println("Your seat is in row $row, seat number $number.")

Your seat is in row E, seat number 5.

Indexing strings

# Customer's seat
seat = "E5"

# Select characters
row = seat[end-1]   # this returns 'E'
number = seat[end]  # this returns '5'

println("Your seat is in row $row, seat number $number.")

Your seat is in row E, seat number 5.

Slicing strings




receipt = "08:30 - coffee - \$3.50"





println(receipt)

08:30 - coffee - $3.50

Slicing strings

# Index position:
#          12345...
receipt = "08:30 - coffee - \$3.50"


time = receipt[1:5]         # Select first 5 characters



println(time)

08:30

Slicing strings

# Index position from end:
#                            4321end
receipt = "08:30 - coffee - \$3.50"

time = receipt[1:5]         # Select first 5 characters

price = receipt[end-4:end]  # Select last 5 characters


println(time)

println(price)

08:30

$3.50

Let's practice!

Introduction to Julia