importrandomimporttime array=[random.randint(0,10)for_inrange(10000)]target=5# 方法一:使用循环遍历数组start_time=time.time()count=count_elements(array,target)end_time=time.time()print("方法一:",count,"耗时:",end_time-start_time,"秒")# 方法二:使用count()方法start_time=time.time()count...
importnumpyasnp arr=np.array([1,2,3,2,1,3,1,1,2,2,2])unique_elements,counts=np.unique(arr,return_counts=True)result=dict(zip(unique_elements,counts))print(result)# 输出结果为:# {1: 4, 2: 5, 3: 2} 1. 2. 3. 4. 5. 6. 7. 8. 9. 方法三:使用pandas.Series.value_counts...
A new array whose items are restricted by typecode, and initializedfrom the optional initializer value, which must be a list, abytes-like object, or iterable over elements of theappropriate type. If given a list or string, the initializer is passed to the new array’sfromlist(), frombytes...
6. 数组中对元素进行布尔类型判断 (python check elements in array with Boolean type) 7. 数组中是否存在满足条件的数 (python check if exsit element in array satisfies a condition) 8. 数组中所有元素是否有0元素 (python check whether all elements in numpy is zero) 9. 数组找到满足一个条件或多个...
color_count.values # 结果 array([ 200, 500, 100, 1000]) 也可以使用索引来获取数据: color_count[2] # 结果 100 1.2.2 DataFrame DataFrame是一个类似于二维数组或表格(如excel)的对象,既有行索引,又有列索引: 行索引,表明不同行,横向索引,叫index,0轴,axis=0 列索引,表名不同列,纵向索引,叫co...
append() -- append a new item to the end of the array buffer_info() -- return information giving the current memory info byteswap() -- byteswap all the items of the array count() -- return number of occurrences of an object extend() -- extend array by appending multiple elements from...
x = cars.count("Lexus") print(x) 输出将返回 int “2” 作为结果,因为“雷克萨斯”在汽车列表中出现了两次。 方法Extend() 使用此方法,可以将列表(或任何可迭代对象)的元素添加到当前列表的末尾。 例: fruits = ["apple", "banana", "cherry"] ...
Get the value of the first array item: x = cars[0] Try it Yourself » Example Modify the value of the first array item: cars[0] ="Toyota" Try it Yourself » The Length of an Array Use thelen()method to return the length of an array (the number of elements in an array). ...
print(len(array)) # create an array of cities cities = ['New York', 'Los Angeles', 'Chicago', 'Houston', 'Phoenix'] # call the function and pass the cities array count_elements(cities) In this script, we define a functioncount_elements(array)that prints the number of elements in th...
array([3, 3, 3, 2, 2, 1, 0, 0, 0, 0], dtype=int64), #ary中元素在out中位置 array([4, 1, 2, 3], dtype=int64)) #元素的count 文件读写: save(file, arr, allow_pickle=True, fix_imports=True):保存数组到文件.npy;savez(...)将多个数组保存到文件.npz; ...