How to take elements from a list embedded in a list?-CodePudding

I have a list made of lists like :

values = [('Part A', 0.1), ('Part B', 0.2), ('Part C', 0.3)]

How can I take only the second element from all the lists within the values list without using a "for" loop?

By using the brackets []

values[0][1]

It outputs the 0.1 value. But when I do

values[:][1]

It outputs both parts of the first list.

Sorry I am a beginner.

CodePudding user response：

One way is using list comprehension

[item[1] for item in values]

Another way is using numpy array

np.array(values)[:,1]

CodePudding user response：

You can use itemgetter to extract a specific item from an object. [list, tuple, dictionary]

itemgetter takes as input an index or a set of indices

Code:

import operator

values = [('Part A', 0.1), ('Part B', 0.2), ('Part C', 0.3)]

all_elements=list(map(operator.itemgetter(0,1),values)) 
second_elements = list(map(operator.itemgetter(1), values)) 

print(all_elements)    #[('Part A', 0.1), ('Part B', 0.2), ('Part C', 0.3)]
print(second_elements) #[0.1, 0.2, 0.3]