ee.List.iterate

किसी सूची पर एल्गोरिदम को दोहराना. इस एल्गोरिदम को दो ऑब्जेक्ट लेने चाहिए. पहला, सूची का मौजूदा आइटम और दूसरा, पिछली बार का नतीजा या पहली बार के लिए, पहले आइटम की वैल्यू.

इस्तेमाल	रिटर्न
List.iterate(function, first)	ऑब्जेक्ट

आर्ग्यूमेंट	टाइप	विवरण
यह: list	सूची
function	एल्‍गोरि‍दम
first	ऑब्जेक्ट

उदाहरण

कोड एडिटर (JavaScript)

// This example uses the ee.List.iterate function to generate a series of
// sequentially halved values.

// Declare a list that will hold the series of sequentially halved values,
// initialize it with the starting quantity.
var quantityList = [1000];

// Define the number of iterations as a list sequence.
var nSteps = ee.List.sequence(1, 10);

// Declare a function that takes the current element of the iteration list and
// the returned result of the previous iteration as inputs. In this case, the
// the function is returning an accumulating list of quantities that are reduced
// by half at each iteration.
var halfOfPrevious = function(currentElement, previousResult) {
  var previousQuantity = ee.Number(ee.List(previousResult).get(-1));
  var currentQuantity = previousQuantity.divide(2);
  return ee.List(previousResult).add(currentQuantity);
};

// Apply the function to the nSteps list, each element is an iteration.
quantityList = ee.List(nSteps.iterate(halfOfPrevious, quantityList));

// Display the results. Note that step 0 is included for the initial value.
print('Steps in the iteration of halved quantities', nSteps);
print('Series of sequentially halved quantities', quantityList);
print(ui.Chart.array.values({
  array: quantityList,
  axis: 0,
  xLabels: ee.List([0]).cat(nSteps)
}));

Python सेटअप करना

Python API और इंटरैक्टिव डेवलपमेंट के लिए geemap का इस्तेमाल करने के बारे में जानकारी पाने के लिए, Python एनवायरमेंट पेज देखें.

import ee
import geemap.core as geemap

Colab (Python)

import matplotlib.pyplot as plt

# This example uses the ee.List.iterate function to generate a series of
# sequentially halved values.

# Declare a list that will hold the series of sequentially halved values,
# initialize it with the starting quantity.
quantity_list = [1000]

# Define the number of iterations as a list sequence.
n_steps = ee.List.sequence(1, 10)


# Declare a function that takes the current element of the iteration list and
# the returned result of the previous iteration as inputs. In this case, the
# the function is returning an accumulating list of quantities that are reduced
# by half at each iteration.
def half_of_previous(current_element, previous_result):
  previous_quantity = ee.Number(ee.List(previous_result).get(-1))
  current_quantity = previous_quantity.divide(2)
  return ee.List(previous_result).add(current_quantity)


# Apply the function to the n_steps list, each element is an iteration.
quantity_list = ee.List(n_steps.iterate(half_of_previous, quantity_list))

# Display the results.
display('Steps in the iteration of halved quantities', n_steps)
display('Series of sequentially halved quantities', quantity_list)
quantity_list_client = quantity_list.getInfo()
plt.scatter(range(len(quantity_list_client)), quantity_list_client)
plt.show()