Ruby Iterative Processing


This will be a memo for learning. This time I would like to summarize various repetitive sentences.

for statement

In the "for" statement, the value is fetched in order from the object specified in advance and repeated.

for counter variable in repeat range do#do is optional
Iterative processing
Example) Pull-down list from 1 to 10 years old in HTML
puts "<select name='age'>"
for age in 1..10
  puts "<option>#{age}age</option"

puts "</select>"

while statement

Repeat the process as long as the conditional expression is true.

#Loop processing by while

#Initialize counter variable
while conditional expression do#do is optional
    #Iterative processing
    #Update counter variable
i=1.              //Initialization of counter variables
while i <=10      //Repeat 1 to 10
  puts i    #Iterative processing
  i=i+1            #Update counter variable

if statement (conditional branch)

if conditional expression
Processing when the conditional expression is satisfied
Processing when the conditional expression is not satisfied
number = 1
if number == 1
  puts "The number is 1"
  puts "The number is not 1"

[Execution result]

The number is 1

Multiple conditional expressions

if conditional expression
Processing when the conditional expression is satisfied
elsif conditional expression 2
Processing when conditional expression 2 is satisfied
Processing when none of the conditional expressions are satisfied

each statement

With each minute, the elements of the array can be taken out in order and processed.

Array.each do |Variable name|
  #The process you want to execute
names = ["Masato","Okachan","Saitou"]

names.each do |name|
  puts "Name is#{name}is"

[Execution result]

The name is Masato
The name is Okachan
The name is Saitou


There may be some mistakes, but I would appreciate it if you could point out that.

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