阅读表的一半部分

Question

当我有一张桌子;

1 0 0 1 0 
0 1 0 1 0 
0 0 1 0 1 
1 1 1 1 0 
0 0 0 0 1 

说我只想读取并保留此表的上部对角线的值，我如何轻松地在纯红宝石中完成此操作？

，使得最终的结构看起来像

1 0 0 1 0 
    1 0 1 1 
    1 0 1 
     1 0 
     1 

感谢

Answer 1

这里假设你有你的表在文件中的某个地方，但你可以基本上只是从不管你想要开始串门：

# get data from file 
data = File.readlines(path).map(&:chomp) 

# convert to array of integers 
a = data.map { |line| line.split(" ").map(&:to_i) } 

# remove incrementally more elements from each row 
a.each_index { |index| a[index].slice!(0,index) } 

# alternatively, you could set these to nil 
# in order to preserve your row/column structure 
a.each_index { |index| index.times { |i| a[index][i] = nil } } 

Answer 2

input = File.new(filename, "rb") 
firstRow = input.readline().split(" ").map { |el| el.to_i } 
len = firstRow.length 
table = [firstRow] 
remaining = input.readlines().map { |row| row.split(" ").map { |el| el.to_i } } 
(len - 1).times { |i| table << remaining[i].slice(i + 1, len - i - 1) } 

Answer 3

我打算假设你的表总是正方形的，而你创建init的方式ial table并不是那么重要。

# Create a two-dimensional array, somehow. 
table = [] 
table << %w{1 0 0 1 0} 
table << %w{0 1 0 1 0} 
table << %w{0 0 1 0 1} 
table << %w{1 1 1 1 0} 
table << %w{0 0 0 0 1} 

# New table 
diagonal = [] 
table.each_with_index {|x,i| diagonal << x[0,table.size - i]} 

# Or go the other direction 
diagonal = [] 
table.each_with_index {|x,i| diagonal << x[0,i+1]} 

如果您需要的值是整数，然后在某处抛出一个map {|i| i.to_i}。