If you're new to Python, there are some common exceptions you'll encounter!

Common errors for beginners in Python

Forget the colon
The misuse of =
Error tighten
Variable not defined
Error caused by Chinese and English input method
Concatenation of different data types
Index position problem
Use keys that do not exist in the dictionary
Forget the brackets
The leakage parameters
Missing dependent library
Python pairs of keywords are used
Coding problem

Forget to write a colon

Forget to add after the if, elif, else, for, while, def statements:

age = 42

if age == 42

    print('Hello! ')
  File "<ipython-input-19-4303141d6f97>", line 2

    if age == 42

                ^

SyntaxError: invalid syntax
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2. Misuse`=`

"Have a problem and no one to answer it? We have created a Python learning QQ group: 857662006 to find like-minded friends and help each other. There are also good video tutorials and PDF e-books in the group. ' ' '= 'is an assignment, and' == gender = 'is used to determine whether two values are equal'male'

if gender = 'male':

    print('Man')
  File "<ipython-input-20-191d01f95984>", line 2

    if gender = 'male':

              ^

SyntaxError: invalid syntax
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3. Wrong indentation

Python uses indentation to distinguish blocks of code. Common errors:

print('Hello! ')

 print('Howdy! ')
  File "<ipython-input-9-784bdb6e1df5>", line 2

    print('Howdy! ')

    ^

IndentationError: unexpected indent
num = 25

if num == 25:

print('Hello! ')
  File "<ipython-input-21-8e4debcdf119>", line 3

    print('Hello! ')

        ^

IndentationError: expected an indented block
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4. Variables are not defined

"Have a problem and no one to answer it? We have created a Python learning QQ group: 857662006 to find like-minded friends and help each other. There are also good video tutorials and PDF e-books in the group. ''' if city in ['New York', 'Bei Jing', 'Tokyo']: print('This is a mega city') --------------------------------------------------------------------------- NameError Traceback (most recent call last) <ipython-input-22-a81fd2e7a0fd> in <module> ----> 1 if city in ['New York', 'Bei Jing', 'Tokyo']: 2 print('This is a mega city') NameError: name 'city' is not definedCopy the code

5. Errors caused by Chinese and English input methods

In English the colon
English parentheses
A comma in English
Single and double quotation marks in English

If 5>3: print('5 >3 ') File "<ipython-input-46-47f8b985b82d>", line 1 if 5>3: ^ SyntaxError: invalid character in identifier if 5>3: Print ('5 larger than 3 ') File "<ipython-input-47-4b1df4694a8d>", line 2 print('5 larger than 3 ') ^ SyntaxError: Invalid character in identifier spam = [1, 2] File "<ipython-input-45-47a5de07f212>", line 1 spam = [1, 2, 3] ^ SyntaxError: invalid character in identifier if 5>3: Print ('5 larger than 3 ') File "<ipython-input-48-ae599f12badb>", line 2 print('5 larger than 3 ') ^ SyntaxError: EOL while scanning string literalCopy the code

6. Splicing of different data types

String/list/tuple concatenation is supported

Dictionary/collection concatenation is not supported

"Have a problem and no one to answer it? We have created a Python learning QQ group: 857662006 to find like-minded friends and help each other. There are also good video tutorials and PDF e-books in the group. ''' 'I have ' + 12 + ' eggs.' #'I have {} eggs.'.format(12) --------------------------------------------------------------------------- TypeError Traceback (most recent call last) <ipython-input-29-20c7c89a2ec6> in <module> ----> 1 'I have ' + 12 + ' eggs.' TypeError: can only concatenate str (not "int") to str ['a', 'b', 'c']+'def' --------------------------------------------------------------------------- TypeError Traceback (most recent call last) <ipython-input-31-0e8919333d6b> in <module> ----> 1 ['a', 'b', 'c']+'def' TypeError: can only concatenate list (not "str") to list ('a', 'b', 'c')+['a', 'b', 'c'] --------------------------------------------------------------------------- TypeError Traceback (most recent call last) <ipython-input-33-90742621216d> in <module> ----> 1 ('a', 'b', 'c')+['a', 'b', 'c'] TypeError: can only concatenate tuple (not "list") to tuple set(['a', 'b', 'c'])+set(['d', 'e']) --------------------------------------------------------------------------- TypeError Traceback (most recent call last) <ipython-input-35-ddf5fb1e6c8c> in <module> ----> 1 set(['a', 'b', 'c'])+set(['d', 'e']) TypeError: unsupported operand type(s) for +: 'set' and 'set' grades1 = {'Mary':99, 'Henry':77} grades2 = {'David':88, 'Unique':89} grades1+grades2 --------------------------------------------------------------------------- TypeError Traceback (most recent call last) <ipython-input-36-1b1456844331> in <module> 2 grades2 = {'David':88, 'Unique':89} 3 ----> 4 grades1+grades2 TypeError: unsupported operand type(s) for +: 'dict' and 'dict'Copy the code

7. Index location problem

spam = ['cat', 'dog', 'mouse'] print(spam[5]) --------------------------------------------------------------------------- IndexError Traceback  (most recent call last) <ipython-input-38-e0a79346266d> in <module> 1 spam = ['cat', 'dog', 'mouse'] ----> 2 print(spam[5]) IndexError: list index out of rangeCopy the code

8. Use keys that don’t exist in the dictionary

To access a key in a dictionary object, use [],

But if this key does not exist, this results in: KeyError: ‘Zebra’

"Have a problem and no one to answer it? We have created a Python learning QQ group: 857662006 to find like-minded friends and help each other. There are also good video tutorials and PDF e-books in the group. ''' spam = {'cat': 'Zophie', 'dog': 'Basil', 'mouse': 'Whiskers'} print(spam['zebra']) --------------------------------------------------------------------------- KeyError Traceback (most recent call last) <ipython-input-39-92c9b44ff034> in <module> 3 'mouse': 'Whiskers'} 4 ----> 5 print(spam['zebra']) KeyError: 'zebra'Copy the code

To avoid this, use the GET method

spam = {'cat': 'Zophie'.'dog': 'Basil'.'mouse': 'Whiskers'}


print(spam.get('zebra'))
None
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If key does not exist, get returns None by default

9. Forget the parentheses

It is easy to omit parentheses when a function or method is passed in

"Have a problem and no one to answer it? We have created a Python learning QQ group: 857662006 to find like-minded friends and help each other. There are also good video tutorials and PDF e-books in the group. ' ' '
spam = {'cat': 'Zophie'.'dog': 'Basil'.'mouse': 'Whiskers'}


print(spam.get('zebra')
  File "<ipython-input-43-100a51a7b630>", line 5

    print(spam.get('zebra')

                           ^

SyntaxError: unexpected EOF while parsing
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10. Parameters are missed

def diyadd(x, y, z):

    return x+y+z


diyadd(1, 2)
---------------------------------------------------------------------------


TypeError                                 Traceback (most recent call last)


<ipython-input-44-7184f3f906ca> in <module>

      2     return x+y+z

      3 

----> 4 diyadd(1, 2)
TypeError: diyadd() missing 1 required positional argument: 'z'
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11. Missing the dependency library

There is no relevant library on the computer

12. Use python keywords

Such as try, except, def, class, object, None, True, False, etc

"Have a problem and no one to answer it? We have created a Python learning QQ group: 857662006 to find like-minded friends and help each other. There are also good video tutorials and PDF e-books in the group. ''' try = 5 print(try) File "<ipython-input-1-508e87fe2ff3>", line 1 try = 5 ^ SyntaxError: invalid syntax def = 6 print(6) File "<ipython-input-2-d04205303265>", line 1 def = 6 ^ SyntaxError: invalid syntaxCopy the code

13. File coding problem

import pandas as pd


df = pd.read_csv('Data/Twitter sentiment analysis dataset. CSV')

df.head()
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Encoding Is passed to UTF-8, GBK

df = pd.read_csv('Data/Twitter sentiment analysis dataset. CSV', encoding='utf-8')

df.head()
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Both encoding is not UTF-8 or GBK, but is not common encoding. We need to pass the correct encoding to run the program.

Python has a chardet library for detecting code.

import chardet


binary_data = open('Data/Twitter sentiment analysis dataset. CSV'.'rb').read()

chardet.detect(binary_data)
{'encoding': 'Windows-1252'.'confidence': 0.7291192008535122.'language': ' '
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If you’re new to Python, there are some common exceptions you’ll encounter!

Common errors for beginners in Python

Forget to write a colon

2. Misuse`=`

3. Wrong indentation

4. Variables are not defined

5. Errors caused by Chinese and English input methods

6. Splicing of different data types

7. Index location problem

8. Use keys that don’t exist in the dictionary

9. Forget the parentheses

10. Parameters are missed

11. Missing the dependency library

12. Use python keywords

13. File coding problem

If you’re new to Python, there are some common exceptions you’ll encounter!

Common errors for beginners in Python

Forget to write a colon

2. Misuse=

3. Wrong indentation

4. Variables are not defined

5. Errors caused by Chinese and English input methods

6. Splicing of different data types

7. Index location problem

8. Use keys that don’t exist in the dictionary

9. Forget the parentheses

10. Parameters are missed

11. Missing the dependency library

12. Use python keywords

13. File coding problem

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2. Misuse`=`