- A+

Category：Languages

Is there a way to use `count()`

where you are looking for a specific value in the nested list and not caring about the rest?

`lst = [[1,6],[1,4],[3,4],[1,2]] X = 1 lst.count([X, _ ]) `

This would return a count of `3`

, since there are three nested lists that have a `1`

in the first index.

Is there a way to do this?

Use some sneaky `sum()`

hacks:

`sum(k[0] == X for k in your_list) `

I.e.

`>>> X = 1 >>> your_list = [[1,6],[1,4],[3,4],[1,2]] >>> sum(k[0] == X for k in your_list) 3 `

**why?**

The section: `k[0] == X for k in your_list`

is a generator expression that yields `True`

for each element in `your_list`

which has first element equal to your `X`

. The `sum()`

function takes the values and treats a `True`

as a `1`

.