如何在PHP中用空格匹配文本文件中的两到三个单词

I am somewhat new to PHP but have created almost everything I need, except one thing which has led me here. I am creating a simple (for you probably but not for me) site for a friend so they can keep track of when they receive rent payments, input new tenants, and check current balances. I had everything working perfect...I thought. When checking the balance, I tested with only one word input to read the text file and output the proper info. But, what I found is if the first and last name are stored with a space between then, I am not getting a match. I need code to read the inputted tenant name in its entirety with the space between. I haven't found anything I could really comprehend and have been searching for several nights. Here is my full code for searching and retrieving results.I am somewhat new to PHP but have created almos