列表中的 Python 递增

Question

我在下面有这段代码：

list = [254,255,256]

# Getting length of list using len() function
length = len(list)
i = 0
counter = 0

while i < length:
  
  url = "https://test/api/v1/implantacao/projeto/{}/tarefa?start={}&limit=50".format(list[i], counter) 
  i += 1
  counter += 1
  print(url) 

Output：

https://test/api/v1/implantacao/projeto/254/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=2&limit=50

但我想要这个 output，列表中每个项目的最后一个数字（计数器）为 0 到 3：

 https://test/api/v1/implantacao/projeto/254/tarefa?start=0&limit=50 
 https://test/api/v1/implantacao/projeto/254/tarefa?start=1&limit=50
 https://test/api/v1/implantacao/projeto/254/tarefa?start=2&limit=50
 https://test/api/v1/implantacao/projeto/254/tarefa?start=3&limit=50
 https://test/api/v1/implantacao/projeto/255/tarefa?start=0&limit=50
 https://test/api/v1/implantacao/projeto/255/tarefa?start=1&limit=50
 https://test/api/v1/implantacao/projeto/255/tarefa?start=2&limit=50
 https://test/api/v1/implantacao/projeto/255/tarefa?start=3&limit=50 

我怎样才能得到这个结果？

Answer 1

计算两个单独列表[254, 255]和[0,1,2,3]的乘积。 然后你可以简单地用一个循环迭代产品中的对。

from itertools import product


template = "https://test/api/v1/implantacao/projeto/{}/tarefa?start={}&limit=50"

for project, start in product([254,255], [0,1,2,3]):
    url = template.format(project, counter)

Answer 2

您可以像这样使用for循环，而不是保留两个计数器：

urlformat = "https://test/api/v1/implantacao/projeto/{}/tarefa?start={}&limit=50"

items = [254,255,256]

for item in items:
    for j in range(4):
        url = urlformat.format(item, j) 
        print(url)

结果：

https://test/api/v1/implantacao/projeto/254/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/254/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/254/tarefa?start=2&limit=50
https://test/api/v1/implantacao/projeto/254/tarefa?start=3&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=2&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=3&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=2&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=3&limit=50

Answer 3

lists = [254,255,256]

# Getting length of list using len() function
length = len(lists)


for li in range(length):
    for count in range(4):
        url = "https://test/api/v1/implantacao/projeto/{}/tarefa?start={}&limit=50".format(lists[li], count)
        print(url) 

结果：

https://test/api/v1/implantacao/projeto/254/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/254/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/254/tarefa?start=2&limit=50
https://test/api/v1/implantacao/projeto/254/tarefa?start=3&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=2&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=3&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=2&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=3&limit=50

永远不要使用内置变量

Answer 4

尝试这个：

    for item in list:
        for i in range(4):
            url = f"https://test/api/v1/implantacao/projeto/{item}/tarefa?start= 
            {i}&limit=50"
            print(url)

在大多数情况下，使用 f 字符串比使用 .format() str 方法要好得多，我建议您阅读 python 文档。 唉，上面的代码会给你你想要的结果。

Answer 5

正如@chepner 所建议的那样，一种可能的方法是计算两个列表的笛卡尔积； 即[254, 255, 256]和[0,1,2,3]以获得：

[(254, 0), (254, 1), (254, 2), (254, 3), (255, 0), (255, 1), (255, 2), (255, 3), (256, 0), (256, 1), (256, 2), (256, 3)]

然后， map匿名 function：

lambda xy: template.format(xy[0], xy[1]),

在该对列表上生成所需的 output，并使用换行符("\n")加入列表。

def main():
    template = "https://test/api/v1/implantacao/projeto/{}/tarefa?start={}&limit=50"
    xs = [254, 255, 256]
    ys = [0, 1, 2, 3]
    cartesianProduct = [(x, y) for x in xs for y in ys]
    print(
        "\n".join(map(
            lambda xy: template.format(xy[0], xy[1]),
            cartesianProduct
        ))
    )

if __name__ == '__main__':
    main()

Output：

https://test/api/v1/implantacao/projeto/254/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/254/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/254/tarefa?start=2&limit=50
https://test/api/v1/implantacao/projeto/254/tarefa?start=3&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=2&limit=50
https://test/api/v1/implantacao/projeto/255/tarefa?start=3&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=0&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=1&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=2&limit=50
https://test/api/v1/implantacao/projeto/256/tarefa?start=3&limit=50