陣列
清單
# Creating a list my_list = [] my_list = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] # List of different data types mixed_list = [1, "hello", 3.14, True] # Accessing elements print(my_list[0]) # Output: 1 print(my_list[-1]) # Output: 5 # Append to the end my_list.append(6) # Insert at a specific position my_list.insert(2, 10) # Find an element in an array index=my_list.find(element) # Remove by value my_list.remove(10) # Remove by index removed_element = my_list.pop(2) # Length of the list print(len(my_list)) # Slicing [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] # sequence[start:stop:step] print(my_list[1:4]) # Output: [1, 2, 3] print(my_list[5:]) # Output: [5, 6, 7, 8, 9] print(my_list[:5]) # Output: [0, 1, 2, 3, 4] print(my_list[::2]) # Output: [0, 2, 4, 6, 8] print(my_list[-4:]) # Output: [6, 7, 8, 9] print(my_list[:-4]) # Output: [0, 1, 2, 3, 4, 5] print(my_list[::-1]) # Output: [9, 8, 7, 6, 5, 4, 3, 2, 1, 0] print(my_list[8:2:-2]) # Output: [8, 6, 4] print(my_list[1:8:2]) # Output: [1, 3, 5, 7] print(my_list[-2:-7:-1]) # Output: [8, 7, 6, 5, 4] # Reversing a list my_list.reverse() # Sorting a list my_list.sort()
排列組合
import itertools # Example list data = [1, 2, 3] # Generating permutations of the entire list perms = list(itertools.permutations(data)) print(perms) # Output: [(1, 2, 3), (1, 3, 2), (2, 1, 3), (2, 3, 1), (3, 1, 2), (3, 2, 1)] # Generating permutations of length 2 perms_length_2 = list(itertools.permutations(data, 2)) print(perms_length_2) # Output: [(1, 2), (1, 3), (2, 1), (2, 3), (3, 1), (3, 2)] combinations(iterable, r) #order does not matter
手動產生排列
您也可以使用遞歸手動產生排列。這是一個簡單的實作:
def permute(arr): result = [] # Base case: if the list is empty, return an empty list if len(arr) == 0: return [[]] # Recursive case for i in range(len(arr)): elem = arr[i] rest = arr[:i] + arr[i+1:] for p in permute(rest): result.append([elem] + p) return result
堆疊
(列表可以用作堆疊)
st=[] st.append() st.pop() top_element = stack[-1]
尖端
1) 脫衣:
它用於從字串中刪除前導和尾隨空格(或其他指定字元)
#EX. (1,2) to 1,2 s.strip('()')
2)不要用普通字典
from collections import defaultdict dictionary=defaultdict(int)
3) 重要檢查與轉換
s.isdigit() s.isalpha() s.isalnum() s.islower() s.isupper() s.lower() s.upper()
4) 重要
round(number, decimal_digits) ord(each)-ord('a')+1 # value of an alphabet #/ (Floating-Point Division) #// (Floor Division) maxim = float('-inf') minim = float('inf') unique_lengths.sort(reverse=True) s.count('x') list1 = [1, 2, 3] iterable = [4, 5, 6] list1.extend(iterable) position.replace('(', '').replace(')', '') expression = "2 + 3 * 4" result = eval(expression) print(result) #Determinant import numpy as arr=[[1,2,3],[3,4,5],[5,6,7]] print(np.linalg.det(np.array(arr)))
已排序
my_list = [3, 1, 4, 1, 5] sorted_list = sorted(my_list) my_tuple = (3, 1, 4, 1, 5) sorted_list = sorted(my_tuple) my_dict = {'apple': 3, 'banana': 1, 'cherry': 2} sorted_keys = sorted(my_dict) my_list = [3, 1, 4, 1, 5] sorted_list = sorted(my_list, reverse=True)
列舉
my_list = ['a', 'b', 'c'] for index, value in enumerate(my_list): print(index, value)
透過物件引用傳遞
不可變類型(如整數、字串、元組):
def modify_immutable(x): x = 10 # Rebinding the local variable to a new object print("Inside function:", x) a = 5 modify_immutable(a) #prints 10 print("Outside function:", a) #prints 5
可變類型(如列表、字典、集合):
def modify_mutable(lst): lst.append(4) # Modifying the original list object print("Inside function:", lst) my_list = [1, 2, 3] modify_mutable(my_list) # [1,2,3] print("Outside function:", my_list) # [1,2,3,4]
Numpy 數組(用於數值運算)
import numpy as np # Creating a 1D array arr_1d = np.array([1, 2, 3, 4, 5]) # Creating a 2D array arr_2d = np.array([[1, 2, 3], [4, 5, 6]]) # Creating an array filled with zeros zeros = np.zeros((3, 4)) # Creating an array filled with ones ones = np.ones((2, 3)) # Creating an array with a range of values range_arr = np.arange(0, 10, 2) # Creating an array with evenly spaced values linspace_arr = np.linspace(0, 1, 5) # Creating an identity matrix identity_matrix = np.eye(3) # Shape of the array shape = arr_2d.shape # Output: (2, 3) # Size of the array (total number of elements) size = arr_2d.size # Output: 6 # Element-wise addition arr_add = arr_1d + 5 # Output: array([6, 7, 8, 9, 10]) # Element-wise subtraction arr_sub = arr_1d - 2 # Output: array([ -1, 0, 1, 2, 3]) # Element-wise multiplication arr_mul = arr_1d * 2 # Output: array([ 2, 4, 6, 8, 10]) # Element-wise division arr_div = arr_1d / 2 # Output: array([0.5, 1. , 1.5, 2. , 2.5]) # Sum total_sum = np.sum(arr_2d) # Output: 21 # Mean mean_value = np.mean(arr_2d) # Output: 3.5 # Standard deviation std_dev = np.std(arr_2d) # Output: 1.707825127659933 # Maximum and minimum max_value = np.max(arr_2d) # Output: 6 min_value = np.min(arr_2d) # Output: 1 # Reshaping reshaped_arr = arr_1d.reshape((5, 1)) # Flattening flattened_arr = arr_2d.flatten() # Transposing transposed_arr = arr_2d.T # Indexing element = arr_2d[1, 2] # Output: 6 # Slicing subarray = arr_2d[0:2, 1:3] # Output: array([[2, 3], [5, 6]])
阿斯型
它是 NumPy 中的一個函數,用於將 numpy 數組轉換為不同的資料類型。
# Datatypes: np.int32,np.float32,np.float64,np.str_ import numpy as np # Create an integer array int_array = np.array([1, 2, 3, 4, 5], dtype=np.int32) # Convert to float float_array = int_array.astype(np.float32) print("Original array:", int_array) print("Converted array:", float_array)
重塑
它是一個強大的工具,可以在不改變數組資料的情況下改變數組的形狀
import numpy as np # Create a 1D array array = np.arange(12) # Reshape to a 2D array (3 rows x 4 columns) reshaped_array = array.reshape((3, 4))
Matplotlib
import numpy as np import matplotlib.pyplot as plt # Create a random 2D array data = np.random.rand(10, 10) # Create a figure with a specific size and resolution plt.figure(figsize=(8, 6), dpi=100) # Display the 2D array as an image plt.imshow(data, cmap='viridis', interpolation='nearest') # Add a color bar to show the scale of values plt.colorbar() # Show the plot plt.show()
字典
# Creating an empty dictionary # Maintains ascending order like map in cpp my_dict = {} # Creating a dictionary with initial values my_dict = {'name': 'Alice', 'age': 25, 'city': 'New York'} # Creating a dictionary using the dict() function my_dict = dict(name='Alice', age=25, city='New York') # Accessing a value by key name = my_dict['name'] # Output: 'Alice' # Using the get() method to access a value age = my_dict.get('age') # Output: 25 country = my_dict.get('country') # Output: None # Adding a new key-value pair my_dict['email'] = 'alice@example.com' # Updating an existing value my_dict['age'] = 26 # Removing a key-value pair using pop() age = my_dict.pop('age') # Removes 'age' and returns its value # Getting all keys in the dictionary keys = my_dict.keys() # Output: dict_keys(['name', 'email']) # Getting all values in the dictionary values = my_dict.values() # Output: dict_values(['Alice', 'alice@example.com']) # Iterating over keys for key in my_dict: print(key) # Iterating over values for value in my_dict.values(): print(value) # Iterating over key-value pairs for key, value in my_dict.items(): print(f"{key}: {value}")
預設字典
from collections import defaultdict d = defaultdict(int) # Initializes 0 to non-existent keys d['apple'] += 1 d['banana'] += 2
放
# Creating an empty set my_set = set() # Creating a set with initial values my_set = {1, 2, 3, 4, 5} # Creating a set from a list my_list = [1, 2, 3, 4, 5] my_set = set(my_list) # Creating a set from a string my_set = set('hello') # Output: {'e', 'h', 'l', 'o'} # Adding an element to a set my_set.add(6) # my_set becomes {1, 2, 3, 4, 5, 6} # Removing an element from a set (raises KeyError if not found) my_set.remove(3) # my_set becomes {1, 2, 4, 5, 6} # Removing and returning an arbitrary element from the set element = my_set.pop() # Returns and removes an arbitrary element
細繩
# Single quotes str1 = 'Hello' # Double quotes str2 = "World" # Triple quotes for multi-line strings str3 = '''This is a multi-line string.''' # Raw strings (ignores escape sequences) raw_str = r'C:\Users\Name' str1 = 'Hello' # Accessing a single character char = str1[1] # 'e' # Accessing a substring (slicing) substring = str1[1:4] # 'ell' # Negative indexing last_char = str1[-1] # 'o' # Using + operator concatenated = 'Hello' + ' ' + 'World' # 'Hello World' # Using join method words = ['Hello', 'World'] concatenated = ' '.join(words) # 'Hello World' name = 'Alice' age = 25 # String formatting formatted_str = f'My name is {name} and I am {age} years old.' # Convert to uppercase upper_str = str1.upper() # 'HELLO WORLD' # Convert to lowercase lower_str = str1.lower() # 'hello world' # Convert to capitalize capital_str = str1.capitalize() # 'Hello world' str1 = ' Hello World ' # Remove leading and trailing whitespace trimmed = str1.strip() # 'Hello World' str1 = 'Hello World Python' # Split the string into a list of substrings split_list = str1.split() # ['Hello', 'World', 'Python'] # Split the string with a specific delimiter split_list = str1.split(' ') # ['Hello', 'World', 'Python'] # Join a list of strings into a single string joined_str = ' '.join(split_list) # 'Hello World Python' str1 = 'Hello World' # Find the position of a substring pos = str1.find('World') # 6 str1 = 'Hello123' # Check if all characters are alphanumeric is_alnum = str1.isalnum() # True # Check if all characters are alphabetic is_alpha = str1.isalpha() # False # Check if all characters are digits is_digit = str1.isdigit() # False # Check if all characters are lowercase is_lower = str1.islower() # False # Check if all characters are uppercase is_upper = str1.isupper() # False
保持聯繫!
如果您喜歡這篇文章,請不要忘記在社交媒體上關注我以獲取更多更新和見解:
推特: madhavganesan
Instagram:madhavganesan
領英: madhavganesan
以上是Python 程式碼片段的詳細內容。更多資訊請關注PHP中文網其他相關文章!

要在有限的時間內最大化學習Python的效率,可以使用Python的datetime、time和schedule模塊。 1.datetime模塊用於記錄和規劃學習時間。 2.time模塊幫助設置學習和休息時間。 3.schedule模塊自動化安排每週學習任務。

Python在遊戲和GUI開發中表現出色。 1)遊戲開發使用Pygame,提供繪圖、音頻等功能,適合創建2D遊戲。 2)GUI開發可選擇Tkinter或PyQt,Tkinter簡單易用,PyQt功能豐富,適合專業開發。

Python适合数据科学、Web开发和自动化任务,而C 适用于系统编程、游戏开发和嵌入式系统。Python以简洁和强大的生态系统著称,C 则以高性能和底层控制能力闻名。

2小時內可以學會Python的基本編程概念和技能。 1.學習變量和數據類型,2.掌握控制流(條件語句和循環),3.理解函數的定義和使用,4.通過簡單示例和代碼片段快速上手Python編程。

Python在web開發、數據科學、機器學習、自動化和腳本編寫等領域有廣泛應用。 1)在web開發中,Django和Flask框架簡化了開發過程。 2)數據科學和機器學習領域,NumPy、Pandas、Scikit-learn和TensorFlow庫提供了強大支持。 3)自動化和腳本編寫方面,Python適用於自動化測試和系統管理等任務。

兩小時內可以學到Python的基礎知識。 1.學習變量和數據類型,2.掌握控制結構如if語句和循環,3.了解函數的定義和使用。這些將幫助你開始編寫簡單的Python程序。

如何在10小時內教計算機小白編程基礎?如果你只有10個小時來教計算機小白一些編程知識,你會選擇教些什麼�...

使用FiddlerEverywhere進行中間人讀取時如何避免被檢測到當你使用FiddlerEverywhere...


熱AI工具

Undresser.AI Undress
人工智慧驅動的應用程序,用於創建逼真的裸體照片

AI Clothes Remover
用於從照片中去除衣服的線上人工智慧工具。

Undress AI Tool
免費脫衣圖片

Clothoff.io
AI脫衣器

AI Hentai Generator
免費產生 AI 無盡。

熱門文章

熱工具

SublimeText3 Linux新版
SublimeText3 Linux最新版

EditPlus 中文破解版
體積小,語法高亮,不支援程式碼提示功能

PhpStorm Mac 版本
最新(2018.2.1 )專業的PHP整合開發工具

SublimeText3 Mac版
神級程式碼編輯軟體(SublimeText3)

記事本++7.3.1
好用且免費的程式碼編輯器