好用到哭！你需要立刻學會的20個Python程式碼段

# Reversing a string using slicing
my_string = "ABCDE"
reversed_string = my_string[::-1]
print(reversed_string)
# Output
# EDCBA

my_string = "my name is chaitanya baweja"
# using the title() function of string class
new_string = my_string.title()
print(new_string)
# Output
# My Name Is Chaitanya Baweja

my_string = "aavvccccddddeee"
# converting the string to a set
temp_set = set(my_string)
# stitching set into a string using join
new_string =   .join(temp_set)
print(new_string)

n = 3 # number of repetitions
my_string = "abcd"
my_list = [1,2,3]
print(my_string*n)
# abcdabcdabcd
print(my_list*n)
# [1,2,3,1,2,3,1,2,3]
import streamlit as st

n = 4
my_list = [0]*n # n denotes the length of the required list
# [0, 0, 0, 0]

# Multiplying each element in a list by 2
original_list = [1,2,3,4]
new_list = [2*x for x in original_list]
print(new_list)
# [2,4,6,8]

a = 1
b = 2
a, b = b, a
print(a) # 2
print(b) # 1

string_1 = "My name is Chaitanya Baweja"
string_2 = "sample/ string 2"
# default separator
print(string_1.split())
# [ My ,  name ,  is ,  Chaitanya ,  Baweja ]
# defining separator as  /
print(string_2.split( / ))
# [ sample ,   string 2 ]

list_of_strings = [ My ,  name ,  is ,  Chaitanya ,  Baweja ]
# Using join with the comma separator
print( , .join(list_of_strings))
# Output
# My,name,is,Chaitanya,Baweja

my_string = "abcba"
m	if my_string == my_string[::-1]:
    print("palindrome")
else:
    print("not palindrome")
# Output
# palindrome

# finding frequency of each element in a list
from collections import Counter
my_list = [ a , a , b , b , b , c , d , d , d , d , d ]
count = Counter(my_list) # defining a counter object
print(count) # Of all elements
# Counter({ d : 5,  b : 3,  a : 2,  c : 1})
print(count[ b ]) # of individual element
# 3

print(count.most_common(1)) # most frequent element
# [( d , 5)]

From collections import Counter
str_1, str_2, str_3 = "acbde", "abced", "abcda"
cnt_1, cnt_2, cnt_3  = Counter(str_1), Counter(str_2), Counter(str_3)
if cnt_1 == cnt_2:
    print( 1 and 2 anagram )
if cnt_1 == cnt_3:
    print( 1 and 3 anagram )

a, b = 1,0
try:
    print(a/b)
    # exception raised when b is 0
except ZeroDivisionError:
    print("division by zero")
else:
    print("no exceptions raised")
finally:
    print("Run this always")

my_list = [ a ,  b ,  c ,  d ,  e ]
for index, value in enumerate(my_list):
    print( {0}: {1} .format(index, value))
# 0: a
# 1: b
# 2: c
# 3: d
# 4: e

import sys
num = 21
print(sys.getsizeof(num))
# In Python 2, 24
# In Python 3, 28

dict_1 = { apple : 9,  banana : 6}
dict_2 = { banana : 4,  orange : 8}
combined_dict = {**dict_1, **dict_2}
print(combined_dict)
# Output
# { apple : 9,  banana : 4,  orange : 8}

import time
start_time = time.time()
# Code to check follows
a, b = 1,2
c = a+ b
# Code to check ends
end_time = time.time()
time_taken_in_micro = (end_time- start_time)*(10**6)
print(" Time taken in micro_seconds: {0} ms").format(time_taken_in_micro)

from iteration_utilities import deepflatten
# if you only have one depth nested_list, use this
def flatten(l):
  return [item for sublist in l for item in sublist]
l = [[1,2,3],[3]]
print(flatten(l))
# [1, 2, 3, 3]
# if you don t know how deep the list is nested
l = [[1,2,3],[4,[5],[6,7]],[8,[9,[10]]]]
print(list(deepflatten(l, depth=3)))
# [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

import random
my_list = [ a ,  b ,  c ,  d ,  e ]
num_samples = 2
samples = random.sample(my_list,num_samples)
print(samples)
# [  a ,  e ] this will have any 2 random values

import secrets                              # imports secure module.
secure_random = secrets.SystemRandom()      # creates a secure random object.
my_list = [ a , b , c , d , e ]
num_samples = 2
samples = secure_random.sample(my_list, num_samples)
print(samples)
# [  e ,  d ] this will have any 2 random values

num = 123456
# using map
list_of_digits = list(map(int, str(num)))
print(list_of_digits)
# [1, 2, 3, 4, 5, 6]
# using list comprehension
list_of_digits = [int(x) for x in str(num)]
print(list_of_digits)
# [1, 2, 3, 4, 5, 6]

def unique(l):
    if len(l)==len(set(l)):
        print("All elements are unique")
    else:
        print("List has duplicates")
unique([1,2,3,4])
# All elements are unique
unique([1,1,2,3])
# List has duplicates