How can I check if a txt file only contains whitespaces-CodePudding

with open('save.txt', 'r') as fname:
    data = fname.readlines()
    print(data)
    x = str(data)
    if x.isspace():
        print("only whitespaces")
    else:
        print("not only whitespaces")

I have tried this but it seems it doesnt work. I want to detect if a txt file only contains whitespaces and also /n if it is possible.

CodePudding user response：

The method readlines() returns a list with every single line. What you want is the read() method, which returns a single string for the whole file. The code would look like this:

with open('save.txt', 'r') as fname:
    data = fname.read()
    print(data)
    if data.isspace():
        print("only whitespaces")
    else:
        print("not only whitespaces")

Also, isspace() already considers \n and \t as whitespace.

CodePudding user response：

readlines() returns a list of strings. You need to check the element of data, not simply convert the list to str.

with open('save.txt', 'r') as fname:
    data = fname.readlines()
    only_whitespace = all(line.isspace() for line in data)
    if only_whitespace:
        print("only whitespaces")
    else:
        print("not only whitespaces")

CodePudding user response：

If you want to detect all whitespace characters (space, newline, tab, vertical space, carriage return...), then isspace might work for you, just read the file as a single string:

with open('save.txt', 'r') as fname:
    data = fname.read()
    print(data)
    if data.isspace():
        print("only whitespaces")
    else:
        print("not only whitespaces")

If you really only want space and newline, you could use a set operation:

with open('save.txt', 'r') as fname:
    data = set(fname.read())
    print(data)
    if data.issubset({' ', '\n'}):
        print("only whitespaces")
    else:
        print("not only whitespaces")