Condiționale

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James Fulton

Climate informatics researcher

Ce sunt expresiile condiționale?

Instruiesc calculatorul să execute o acțiune dacă o condiție este îndeplinită
Permit scrierea de cod care ia propriile decizii

is_raining = true


# Conditional expression
if is_raining

    println("Better get your coat")
end

Better get your coat

Ce sunt expresiile condiționale?

Instruiesc calculatorul să execute o acțiune dacă o condiție este îndeplinită
Permit scrierea de cod care ia propriile decizii

is_raining = true 


# Conditional expression
if is_raining

println("Better get your coat")
end

Better get your coat

Ce sunt expresiile condiționale?

is_raining = false

# Conditional expression
if is_raining
    println("Better get your coat")
end

Mai multe linii de cod în instrucțiunea `if`

is_raining = true

if is_raining
    # This can be many lines of code

    println("The weather is awful")
    println("Better get your coat")

end

# Code below end is always run
println("Ready to go")

The weather is awful
Better get your coat
Ready to go

is_raining = false

if is_raining
    # This can be many lines of code
    println("The weather is awful")
    println("Better get your coat")
end

# Code below end is always run
println("Ready to go")

Ready to go

Comparații

Când plouă:

amount_of_rain = 1.


# Use comparison
is_raining = amount_of_rain > 0


println(is_raining)

true

Când e uscat:

amount_of_rain = 0.


# Use comparison
is_raining = amount_of_rain > 0


println(is_raining)

false

Comparații

Când plouă:

amount_of_rain = 1.

# Use comparison
is_raining = amount_of_rain > 0

# Conditional expression
if is_raining
    println("Better get your coat")
end

Better get your coat

Când e uscat:

amount_of_rain = 0.

# Use comparison
is_raining = amount_of_rain > 0

# Conditional expression
if is_raining
    println("Better get your coat")
end

Comparații

Când plouă:

amount_of_rain = 1.




# Conditional expression
if amount_of_rain>0
    println("Better get your coat")
end

Better get your coat

Când e uscat:

amount_of_rain = 0.




# Conditional expression
if amount_of_rain>0
    println("Better get your coat")
end

Alte comparații

a == b verifică dacă două valori sunt egale

a = 1.


# Value of a is 1?
println(a==1)

true

# Data type of a is Float64?
println(typeof(a)==Float64)

true

Alte comparații

a == b verifică dacă două valori sunt egale
a != b verifică dacă două valori sunt diferite

a = 1.


# Value of a is not 1?
println(a!=1)

false

# Data type of a is not Float64?
println(typeof(a)!=Float64)

false

Alte comparații

a == b verifică dacă două valori sunt egale
a != b verifică dacă două valori sunt diferite
a > b verifică dacă a este mai mare decât b
a >= b verifică dacă este mai mare sau egal

a = 1.


# a is greater than 1?
println(a>1)

false

# a is greater than or equal to 1?
println(a>=1)

true

Alte comparații

a == b verifică dacă două valori sunt egale
a != b verifică dacă două valori sunt diferite
a > b verifică dacă a este mai mare decât b
a >= b verifică dacă este mai mare sau egal
a < b verifică dacă a este mai mic decât b
a <= b verifică dacă este mai mic sau egal

a = 1.


# a is less than 1?
println(a<1)

false

# a is less than or equal to 1?
println(a<=1)

true

Când condiția nu este îndeplinită

amount_of_rain = 0.

if amount_of_rain == 0
    # Do this if conditon is met
    println("The sky looks clear")

else
    # Do this if not met
    println("Better get your coat")

end

The sky looks clear

amount_of_rain = 5.

if amount_of_rain == 0
    # Do this if conditon is met
    println("The sky looks clear")
else
    # Do this if not met
    println("Better get your coat")
end

Better get your coat

Condiții suplimentare

amount_of_rain = 0.

if amount_of_rain == 0
    println("There is zero rain")

elseif amount_of_rain < 1
    # Add a second condition
    println("Better get your coat")

else
    println("That's a lot of rain, stay home")
end

There is zero rain

Condiții suplimentare

amount_of_rain = 0.5

if amount_of_rain == 0
    println("There is zero rain")
elseif amount_of_rain < 1
    # Add a second condition
    println("Better get your coat")
else
    println("That's a lot of rain, stay home")
end

Better get your coat

Condiții suplimentare

amount_of_rain = 2

if amount_of_rain == 0
    println("There is zero rain")
elseif amount_of_rain < 1
    # Add a second condition
    println("Better get your coat")
else
    println("That's a lot of rain, stay home")
end

That's a lot of rain, stay home

Mai multe ramuri `elseif`

amount_of_rain = 2

if amount_of_rain == 0
    println("There is zero rain")
elseif amount_of_rain < 1     # <--- many elseif conditions
    println("Better get your coat")
elseif amount_of_rain < 5     # <--- many elseif conditions
    println("You're going to need a bigger coat")
else
    println("That's a lot of rain, stay home")
end

You're going to need a bigger coat

Să exersăm!

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