Operators

Operators allow calculating, comparing and combining conditions.

Arithmetic#

print 10 + 5 * 2    # 20
print (10 + 5) * 2  # 30
print 10 / 3        # 3.3333...
print 10 // 3       # 3
print 10 % 3        # 1
print 2 ** 4        # 16

x = "5"
y = "5.5"
print x + 3     # 8
print x + 0     # 5
print y + x     # 10.5

Comparison#

These operators compare two values and return true or false:

Use them in conditions:

age = 18
if age >= 18
  print "You are of legal age"

print "Is 5 equal to 10? " 5 == 10  # false
print "Is 12 an even number? " 12 % 2 == 0  # true

Logical#

They combine conditions or invert them:

Practical example:

age = 25
has_license = true
if age >= 18 and has_license
  print "You can drive"

# If the first condition is false, the second is not executed
if false and input("This input will not execute") 
  print "This will not be printed"

# If the first condition is true, the second is not executed
if true or input("This input will not execute") 
  print "This will be printed"

Concatenation#

The . operator (with spaces around it) joins values as text:

x = 4
y = 1.05
result = "The number is " . x . y
print result # "The number is 41.05"

Reading#

The <- operator asks for a value that the user must enter manually.

name <- "Enter your name: "
age <- "Enter your age: "
print "Hello " name ", you are " age " years old"

Compound assignment#

Modify a variable in a single line:

Example:

counter = 0
counter += 5
counter++
print counter   # 6