# 七、Rails语法

# Time

api-day (opens new window)

# time TO 2016-06-04
Time.at(@romantic_order.consume_time + 1.day - Time.now).utc.strftime("%H:%M:%S")

# 循环语句

if
```
if true

elsif

end
```

case

case name
  when "John"
    puts "Howdy John!"
  when "Ryan"
    puts "Whatz up Ryan!"
  else
    puts "Hi #{name}!"
end

真假

只有false和nil是假，其他都为真

# Array

# 将 nil 对象踢出！！！！
Array.wrap([nil])
# 带 index 的遍历
  def count(array, status)
    array.select{|i| i.status == status}.length
  end

# array

@suggested_horses.include?(horse)

# JSON

JSON["calendars"].each do |key, value|
  # working with value["busy"]...
end

# date

# 获得今天星期几
Time.now.wday

# 日期转换
Time.now.strftime("%Y-%m-%d %H:%M:%S")  #2016-05-23 14:32:32

# 字符串 to Time
return "2016-01-01".to_time

# 获得本周开始日期
Date.today.beginning_of_week

# 获得本周开始时间
Time.now.beginning_of_week

# 获得今天开始
Time.now.beginning_of_day

Time.now + 10.minutes
Time.now + 10.seconds

将时间转换为小时：分钟：秒

    def time_diff(start_time, end_time)
      seconds_diff = (start_time - end_time).to_i.abs

      hours = seconds_diff / 3600
      seconds_diff -= hours * 3600

      minutes = seconds_diff / 60
      seconds_diff -= minutes * 60

      seconds = seconds_diff
      "#{hours.to_s.rjust(2, '0')}:#{minutes.to_s.rjust(2, '0')}:#{seconds.to_s.rjust(2, '0')}"
    end

# 判断非空

present? 可判断 [],{},"",都为空
nil?
blank?

# SCSS文件中使用 assets

.right-bar-filler{
    background:url(asset-path('right_bar_filler.jpg', image)) repeat-y;
    padding-top:0px;}

# string

转换为 symble

# 语法
str.intern => symbol
str.to_sym => symbol

# 例子
"Koala".intern         #=> :Koala
s = 'cat'.to_sym       #=> :cat
s == :cat              #=> true
s = '@cat'.to_sym      #=> :@cat
s == :@cat             #=> true

处理空格

# 去除两端空格
"   I have leading and trailing white space   ".strip

# 取出行内空格
"I have white space".delete(' ')

# regex 去除空格换行等
"   I have leading and trailing white space   ".gsub(/\s+/, "")

← Rails_常用命令