Summarize some common mistakes of python developers (on)

The file name is the same as the package name to be quoted

For example, if you want to quote requests, but you name your own file also requests.py, then execute the following code

import requests
requests.get('http://www.baidu.com')

Will report the following error

AttributeError: module 'requests' has no attribute 'get'

The solution is to change the name of your python file, as long as it is not the same as the package name. If you really don’t want to change the file name, you can use the following method

import sys
_cpath_ = sys.path[0]
print(sys.path)
print(_cpath_)
sys.path.remove(_cpath_)
import requests
sys.path.insert(0, _cpath_)

requests.get('http://www.baidu.com')

The main principle is to exclude the current directory from the search directory of python running. After this processing, executing python requests.py on the command line can run normally, but debugging and running in pycharm fails.

Format misalignment problem

Below is a piece of normal code

def fun():
    a=1
    b=2
    if a>b:
        print("a")  
    else:
        print("b")

fun()

1. If the else is not aligned

def fun():
    a=1
    b=2
    if a>b:
        print("a")  
     else:
        print("b")

fun()

Will report

IndentationError: unindent does not match any outer indentation level

2. If else and if do not appear in pairs, such as directly writing an else or writing an extra else, or omission of the colon after if and else

def fun():
    a=1
    b=2
    else:
        print("b")

fun()

def fun():
    a=1
    b=2
    if a>b:
        print("a")
    else:
        print("b")
    else:
        print("b")

fun()

def fun():
    a=1
    b=2
    if a>b:
        print("a")
    else
        print("b")

fun()

Metropolis

SyntaxError: invalid syntax

3. If the statements below if and else are not indented

def fun():
    a=1
    b=2
    if a>b:
    print("a")
    else:
    print("b")

fun()

Will report

IndentationError: expected an indented block

Use Chinese quotation marks for strings

For example, use Chinese quotation marks below

print(“a”)

Will report

SyntaxError: invalid character in identifier

The correct way is to use English single or double quotes

print('b')
print("b")