我怎样才能大写的数组中的每个元素？ [英] How can I uppercase each element of an array?

问题描述

我怎样才能把元素融入大写的数组？预期的产出将是：

  [星期一，星期二，星期三，星期四，星期五]
= GT; [周一周二周三周四周五]
 

以下没有工作，把它们作为小写。

  Day.weekday.map（安培;：名）。每个{| the_day | the_day.upcase}
 = GT; [周一周二周三周四周五]
 

解决方案

返回一个新的阵列

如果您想返回一个大写的数组，使用 #map

 数组= [星期一，星期二，星期三，星期四，星期五]＃返回的大写的版本。
array.map（安培;：upcase）
= GT; [周一周二周三周四周五]＃返回原始的，未经修改的数组。
排列
= GT; [周一周二周三周四周五]
 

正如你所看到的，原始数组不会被修改，但可以使用从#map的大写的返回值的任何地方，你可以使用一个前pression。

位置

更新阵列

如果你想为大写就地阵列，使用 #map 而不是：

 数组= [星期一，星期二，星期三，星期四，星期五]
array.map（安培;：upcase）！
排列
= GT; [周一周二周三周四周五]
 

How can I turn an array of elements into uppercase? Expected output would be:

["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]  
=> ["MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY"]

The following didn't work and left them as lower case.

Day.weekday.map(&:name).each {|the_day| the_day.upcase }
 => ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"] 

解决方案

Return a New Array

If you want to return an uppercased array, use #map:

array = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]

# Return the uppercased version.
array.map(&:upcase)
=> ["MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY"]

# Return the original, unmodified array.
array
=> ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]

As you can see, the original array is not modified, but you can use the uppercased return value from #map anywhere you can use an expression.

Update Array in Place

If you want to uppercase the array in-place, use #map! instead:

array = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]
array.map!(&:upcase)
array
=> ["MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY"]

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