Does pandas.read_csv loads all data at once?
The way to check is len(df). This will give you the number of lines in DataFrame.  Then, you need to check the csv file for lines. On linux, use wc -l. Or, you may need to use something else to findout lines in csv. Notepad++, Nano, SumlineText.
I want to know when I use pandas.read_csv('file.csv') function to read csv file, did it load all data of file.csv into DataFrame?