计算文件夹中多个文件的两列之间的R²，并使用R将结果写入一个文件

I have multiple .txt files in a folder, each having multiple columns. I want to calculate r squared value between col 2 and 7 of each file and print the same into one output file. I tried following for one file and it works:I have multiple .txt files in a folder, each ha