np.where（）

`np.where()`是一个NumPy库中的函数，用于根据给定的条件返回输入数组中的元素。它有两种用法：

1. `np.where(condition, x, y)`：当满足条件时输出x，不满足条件则输出y。

举个例子：

import numpy as np

a = np.arange(10)
print(np.where(a > 5, 1, -1))
# 输出：array([-1, -1, -1, -1, -1, -1, 1, 1, 1, 1])

2. `np.where(condition)`：只有条件(condition)为True时才返回非零元素的索引。

举个例子：

import numpy as np

a = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
print(np.where(a > 5))
# 输出：(array([1, 2, 2, 2]), array([2, 0, 1, 2]))

上面的代码中，输出的是满足条件a>5的元素的索引。

相关问题

np.where(Self_Time < Hour[np.min(np.where(Hour == Country_Time[i])) + 1]), np.inf, np.nan)

As an AI language model, I cannot provide a definitive answer without additional context and information about the variables and the code block. However, I can provide some general information about the np.where() function and the code snippet you provided.

The np.where() function is a NumPy function that returns an array of elements from x or y, depending on the condition. The syntax of np.where() is as follows:

np.where(condition, x, y)

- condition: A boolean array or a condition that evaluates to a boolean array.
- x: An array-like object that has the same shape as the condition. It is used to select elements where the condition is True.
- y: An array-like object that has the same shape as the condition. It is used to select elements where the condition is False.

In the code snippet you provided, the np.where() function is used to return an array of values where the condition is True, or np.inf (positive infinity) where the condition is False. The condition is:

Self_Time < Hour[np.min(np.where(Hour == Country_Time[i])) + 1]

This condition compares the values in the Self_Time array with the value in the Hour array at the index returned by np.min(np.where(Hour == Country_Time[i])) + 1. The np.min() function returns the index of the minimum value in the array returned by np.where(). The +1 is added to the index to get the next value in the Hour array.

Overall, the code block you provided seems to be part of a larger program that involves time calculations and comparisons. Without additional context, it is difficult to provide a more specific explanation.

np.where

`np.where()` 是 NumPy 库中的一个函数，用于根据给定的条件从数组中选择元素。它的语法如下：

np.where(condition[, x, y])

其中，`condition` 是一个布尔型数组，表示需要进行选择的元素的条件；`x` 和 `y` 是可选参数，表示在满足条件和不满足条件时的选择。如果只给出 `condition` 参数，则返回满足条件的元素的索引；如果同时给出 `x` 和 `y` 参数，则返回一个数组，其中满足条件的元素用 `x` 参数对应的值替换，不满足条件的元素用 `y` 参数对应的值替换。