Python Learning Knowledge Base

>>> with open ("Login.txt", "r+", ending= "Utf-8") as F:

... f.readline ()

File "<stdin>", Line 2 f.readline () ^ indentationerror:expected an indented block

Cause: No indentation, add a space or tab to a new line

With open ("Users_info", "RW", encoding= "Utf-8") as F:for line in F:

If "Lisi" in line:

F.seek (F.tell ()-len (line))

Line= "Test 123 0"

F.write (line)

Oserror:telling position disabled by next () call

Why: Tell () cannot be used in a loop, the specific reason needs to be studied in depth

Typeerror:eval () Arg 1 must be a string, bytes or code object

Reason: Use the eval () method on a type that is not a Str,bytes,code object, such as I set a = {"Zhangsan" in Terminal, "123"},eval (a), which is the eval () method for the dictionary, the correct way is a= ' {" Zhangsan "," 123 "} ', Eval (a)

Python module and import appear importerror:no module named ' xxx ' problem

Reason: According to my experience in Java, the import error is because the code is placed under the direction (package), so the import is to add the prefix

For example: If the test.py file is established under module M1, import should be imported M1.test

PEP8 Code Style Error

Expected 2 blank lines, found 0 need two lines blank, 0 rows found

Cause: The file code should be empty two lines behind the comment

Typo:in Word incorrectly spelled

Cause: Word spelling error

variables, values, operators should be preceded by a space, comma should be followed by a space, the output string should be used such as "test%s", the% name, before and after the space

Python Learning Knowledge Base