17 useful Python tips to share!

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Hello everyone, I am Python artificial intelligence technology.

In this article, we will discuss the most commonly used python tricks. Most of these techniques are simple Tricks that I use in my daily work, and I think good things should be shared with everyone.

Without further ado, let’s get started! :)

Tips summary

1. Handling multiple inputs from the user

Sometimes we need to get multiple inputs from the user in order to use a loop or any iteration, generally The writing method is as follows:

# bad practice码
n1 = input("enter a number : ")
n2 = input("enter a number : ")
n2 = input("enter a number : ")
print(n1, n2, n3)

But a better processing method is as follows:

# good practice
n1, n2, n3 = input("enter a number : ").split()
print(n1, n2, n3)

2. Processing multiple conditional statements

If we need to check multiple conditional statements in the code, At this point we can use the all() or any() function to achieve our goal. Generally, all() is used when we have multiple and conditions and any() is used when we have multiple or conditions. This usage will make our code clearer and easier to read, and will help us avoid trouble when debugging.

The general example for all() is as follows:

size = "lg"
color = "blue"
price = 50
# bad practice
if size == "lg" and color == "blue" and price < 100:
 print("Yes, I want to but the product.")

A better processing method is as follows:

# good practice
conditions = [
 size == "lg",
 color == "blue",
 price < 100,
]
if all(conditions):
 print("Yes, I want to but the product.")

The general example for any() is as follows:

# bad practice
size = "lg"
color = "blue"
price = 50
if size == "lg" or color == "blue" or price < 100:
 print("Yes, I want to but the product.")

A better way to handle it is as follows:

# good practice
conditions = [
 size == "lg",
 color == "blue",
 price < 100,
]
if any(conditions):
 print("Yes, I want to but the product.")

3. Determine number parity

This is easy to implement, we get the input from the user, convert it to an integer, check for the number 2 The remainder operation of , if the remainder is zero, it is an even number.

print('odd' if int(input('Enter a number: '))%2 else 'even')

4. Exchange variables

If we need to exchange the value of a variable in Python, we do not need to define a temporary variable to operate. We generally use the following code to implement variable exchange:

v1 = 100
v2 = 200
# bad practice
temp = v1
v1 = v2
v2 = temp

But a better processing method is as follows:

v1 = 100
v2 = 200
# good practice
v1, v2 = v2, v1

5. Determine whether the string is a palindrome string

Change the characters The simplest way to reverse a string is [::-1], the code is as follows:

print("John Deo"[::-1])

6. Reverse a string

Determine whether a string is a palindrome in Python String, just use the statement

string.find(string[::-1])== 0, the sample code is as follows:

v1 = "madam" # is a palindrome string
v2 = "master" # is not a palindrome string
print(v1.find(v1[::-1]) == 0) # True
print(v1.find(v2[::-1]) == 0) # False

7. Try to use Inline if statement

Most of the time, we only have one statement after the condition, so using Inline if statement can help us write more concise code. For example, the general writing method is:

name = "ali"
age = 22
# bad practices
if name:
 print(name)
if name and age > 18:
 print("user is verified")

But a better processing method is as follows:

# a better approach
print(name if name else "")
""" here you have to define the else condition too"""
# good practice
name and print(name)
age > 18 and name and print("user is verified")

8. Delete duplicate elements in the list

We don’t need to traverse the entire list List to check for duplicate elements, we can simply use set() to delete duplicate elements, the code is as follows:

lst = [1, 2, 3, 4, 3, 4, 4, 5, 6, 3, 1, 6, 7, 9, 4, 0]
print(lst)
unique_lst = list(set(lst))
print(unique_lst)

9. Find the most repeated elements in the list

You can use max in Python ( ) function and pass list.count as key, you can find the element with the most repetitions in the list. The code is as follows:

lst = [1, 2, 3, 4, 3, 4, 4, 5, 6, 3, 1, 6, 7, 9, 4, 0]
most_repeated_item = max(lst, key=lst.count)
print(most_repeated_item)

10. List generation

My favorite in Python The function of List Comprehension is list comprehensions. This feature allows us to write very concise and powerful code, and these codes read almost as easy to understand as natural language. An example is as follows:

numbers = [1,2,3,4,5,6,7]
evens = [x for x in numbers if x % 2 is 0]
odds = [y for y in numbers if y not in evens]
cities = ['London', 'Dublin', 'Oslo']
def visit(city):
 print("Welcome to "+city)
for city in cities:
 visit(city)

11. Use *args to pass multiple parameters

In Python, we can use *args to pass multiple parameters to a function. An example is as follows:

def sum_of_squares(n1, n2)
 return n1**2 + n2**2
print(sum_of_squares(2,3))
# output: 13
"""
what ever if you want to pass, multiple args to the function
as n number of args. so let's make it dynamic.
"""
def sum_of_squares(*args):
 return sum([item**2 for item in args])
# now you can pass as many parameters as you want
print(sum_of_squares(2, 3, 4))
print(sum_of_squares(2, 3, 4, 5, 6))

12. Processing subscripts during loops

Sometimes when we are working, we want to get the subscripts of elements in the loop. Generally speaking, the more elegant way of writing is as follows:

lst = ["blue", "lightblue", "pink", "orange", "red"]
for idx, item in enumerate(lst):
print(idx, item)

13. Splicing multiple elements in the list

In Python, the Join() function is generally used to splice all the elements in the list together. Of course, we can also add splicing symbols when splicing. The example is as follows:

names = ["john", "sara", "jim", "rock"]
print(", ".join(names))

14. Merge the two dictionaries

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In Python we can use {**dict_name, **dict_name2, …} to merge multiple dictionaries. The example is as follows:

d1 = {"v1": 22, "v2": 33}
d2 = {"v2": 44, "v3": 55}
d3 = {**d1, **d2}
print(d3)

The result is as follows:

{'v1': 22, 'v2': 44, 'v3': 55}

15 Use two lists to generate a dictionary

In Python, if we need to combine the corresponding elements in the two lists into a dictionary, then we can use the zip function to easily do this. The code is as follows:

keys = ['a', 'b', 'c']
vals = [1, 2, 3]
zipped = dict(zip(keys, vals))

16. Sort the dictionary according to value

In Python we use the sorted() function to sort the dictionary according to its value. The code is as follows:

d = {
 "v1": 80,
 "v2": 20,
 "v3": 40,
 "v4": 20,
 "v5": 10,
}
sorted_d = dict(sorted(d.items(), key=lambda item: item[1]))
print(sorted_d)
当然我们也可以使用itemgetter( )来替代上述 lambda函数,代码如下:
from operator import itemgetter
sorted_d = dict(sorted(d.items(), key=itemgetter(1)))

Further, we can also sort it in descending order by passing reverse=True:

sorted_d = dict(sorted(d.items(), key=itemgetter(1), reverse=True))

17, Pretty print

Using the Print() function in Python, sometimes the output It's ugly. At this time, we can use pprint to make the output more beautiful. The sample is as follows:

from pprint import pprint
data = {
 "name": "john deo",
 "age": "22",
 "address": {"contry": "canada", "state": "an state of canada :)", "address": "street st.34 north 12"},
 "attr": {"verified": True, "emialaddress": True},
}
print(data)
pprint(data)

The output is as follows:

{'name': 'john deo', 'age': '22', 'address': {'contry': 'canada', 'state': 'an state of canada :)', 'address': 'street st.34 north 12'}, 'attr': {'verified': True, 'emialaddress': True}}
{'address': {'address': 'street st.34 north 12',
'contry': 'canada',
'state': 'an state of canada :)'},
'age': '22',
'attr': {'emialaddress': True, 'verified': True},
'name': 'john deo'}

It can be seen that using the pprint function can make the output of the dictionary easier to read.

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