它如何获取列表列表中的特定参数？

Question

for example we have;

L = [["Ak","154"],["Bm","200"],["Ck","250"], ["Ad","500"],["Ac","600"]]

I want to choose first element starting with 'A' I want to find their values which are in second element; see this output should like

["154","500","600"] or like [["154"],["500"],["600"]]

Answer 1

Filter and map with a list comprehension:

[b for a, b in L if a[0] == "A"]

Or, if you need to search for prefixes of more than one character:

[b for a, b in L if a.startswith("A")]

Answer 2

Another Solution Using map() and filter() functions

L = [["Ak","154"],["Bm","200"],["Ck","250"], ["Ad","500"],["Ac","600"]]

k = list(map(lambda y:y[1], list(filter(lambda x: x[0][0] == 'A' , L))))

Output:

['154', '500', '600']