nativo interview

Question 1

git: to make git ignore certain files

Answer 1

before you commit, create a .gitignore file and add them into it.

Question 2

git: A good commit message

Answer 2

is written as a command. “Remove the cruft”

and the body is, what, why and how.

“Add user accounts to allow user logins by integrating django allauth”

Question 3

Python: To stop a for loop, use the command

Answer 3

break

Question 4

Python: To test if a number is even, type

Answer 4

number % 2 == 0

Question 5

Python: To switch the keys and values of a dictionary to be the values and keys using a dict comprehension, type

Answer 5

{value: key for key, value in my_dict.items()}

Question 6

Python: __init__ is a

Answer 6

method that runs right when a class is instantiated

Question 7

Python: An alternative to putting all of the parameters and defaults in a class’s def __init__(self, my_attribute=1, my_attribute2=2): you can just type

Answer 7

class Myclass:
    def \_\_init\_\_(self, **args):
        self.my_attribute = args.get("Name", "Bill")
        self.my_attribute2 = args.get("Age", 20)

Question 8

Python: Every method in a class must at least take the

Answer 8

self argument. def my_method(self):

Question 9

Python: The (self) argument represents

Answer 9

the data from the instance you are calling the method on.

Question 10

Python: Using self. in a class method allows you to

Answer 10

access the attributes of the instance you are calling the method on.

Question 11

Python: This function will return
def f():
    return

f()

Answer 11

None

Question 12

Python and Javascript imports start with

Answer 12

Python = from 
Javascript =  import

PFJI

Question 13

Python: To create a class that takes two arguments upon instantiation, and has a method, type

Answer 13

class Myclass:
    def \_\_init\_\_(self, arg_1="default1", arg_2="default2"):
        self.arg_1 = arg_1
        self.arg_2 = arg_2
    def my_method(self):
        return self.arg_one*2

Question 14

Python: To return a random list item, type

Answer 14

import random

random.choice(my_list)

Question 15

Python: To capture any parameters that are passed into a class when being instantiated, but were not defined inside the class beforehand, type

Answer 15

class Myclass:
    def \_\_init\_\_(self, **args)
        self.my_attribute = args.get("arg", "default")
        for key, value in args.items():
            setattr(self, key, value)

Question 16

JS: “use strict” is

Answer 16

a string you can add to the top of a file or function in order to

Question 17

CS: The difference between an error and an exception is

Answer 17

An Error indicates a serious problem you should not try to catch. An Exception indicates a problem you might want to catch.

Question 18

Python: A decorator is just

Answer 18

syntactic sugar for creating a closure

Question 19

Python: The three ways to wrap a closure around a function and call it are

def add(a, b):
    return a + b

Answer 19

@closure_function_name
def add(a, b):
    return a + b

add(1, 1)

or

add = closure_function_name(add)
add(1,1)

or

closure_function_name(add)(1, 1)

https: //www.youtube.com/watch?v=swU3c34d2NQ
https: //www.youtube.com/watch?v=MYAEv3JoenI

Question 20

Python: Using a closure wrapper gives you an opportunity to

Answer 20

perform some operations before calling the original function (like logging) or altering the passed in parameters before passing them into original function or making the calling of the original function conditional

Question 21

Python: A generator is

Answer 21

an object you can iterate on without loading the entire list into memory.

Question 22

Python: To create a generator, type

Answer 22

the steps are: make the generator function, then call it with your list.

def generator_function(iterable):
    for item in iterable:
        yield item * item

generator = generator_function([1,2,3])

or a generator comprehension

generator = (item * item for item in [1,2,3])

Question 23

Python: In functions, the yield keyword

Answer 23

sends the value passed to yield to the caller and pauses the function, but retains enough state so that it can resume when you call next(generator())
e.g.

def simpleGenerator(): 
    yield 1
    yield 2
    yield 3

for value in simpleGenerator():
print(value)

1
2
3

Question 24

Python: To get the results of a generator, type

Answer 24

next(generator)

or

for item in generator:
…

Question 25

Python: A closure is basically

Answer 25

closure_function(passed_in_function)(param1, param2)

a closure function gets called
puts the passed in function into the closure_function scope
can define some variables
defines an inside function which will maintain access to the closure_functions scope
the closure function returns a pointer to the inside function
the inside function gets called with parameters (must match number of params)
can do side effects, alter the parameters and call the passed_in_function with the parameters it was given

The closure_functions variables can be changed by using nonlocal variable_name

you create a function that takes a passed in function as a parameter, it has an inside function, and returns a pointer to the inside function. The inside function receives the parameters that you send into the closure when you call it and then you can manipulate the parameters or cause side effects or conditionally call the passed in function with new params

Question 26

Python: the order of where python looks for variable definitions is

Answer 26

LEGB

Local, Enclosing, Global, Built-in

Question 27

Python: To be able to change the value of a variable defined outside a function from inside a function, type

Answer 27

x = 10

def my_function():
    global x  #if it is defined the module level scope
    x = 20

or

def my_function():
    nonlocal x  #if it is defined in another function this function is nested it
    x = 20

https://www.youtube.com/watch?v=QVdf0LgmICw

Question 28

Python: A lambda function is

Answer 28

an anonymous function usually used for inline functions

Question 29

In python and JS everything is

Answer 29

an object

Question 30

JS: To have multiple callback functions type

Answer 30

function printList(callback) {
  // do your printList work
  console.log('printList is done');
  callback();
}

function updateDB(callback) {
  // do your updateDB work
  console.log('updateDB is done');
  callback()
}

function getDistanceWithLatLong(callback) {
  // do your getDistanceWithLatLong work
  console.log('getDistanceWithLatLong is done');
  callback();
}

function runSearchInOrder(callback) {
    getDistanceWithLatLong(function() {
        updateDB(function() {
            printList(callback);
        });
    });
}

runSearchInOrder(function(){console.log(‘finished’)});

The output will be:
getDistanceWithLatLong is done
updateDB is done
printList is done
finished

Question 31

JS: To make a function that takes a callback function, type

Answer 31

function funcName(callback) {
console.log(‘hi’)
callback()
}

funcName(function() {
console.log(‘there’)
})

or with arrows

let funcName = (callback) => {
console.log(‘hi’)
callback()
}

funcName(()=>{
console.log(‘there’)
})

the callback function passed into the calling function usually runs last

Question 32

JS: How a promise works is,

Answer 32

it runs the initial script inside the Promise declaration
new Promise(function(resolve, reject) {
setTimeout(() => resolve(1), 1000); // (*)
}).then(…)
and waits for resolve to be called inside the promise
After resolve is called .then() runs the function you passed in and uses the prior resolve value as the parameters
this .then function returns a promise and it uses the return value of your passed in function as the resolve value
it runs the next .then() or your function can return another promise and it will use the resolve value of that promise to pass into the next .then() function.

https://javascript.info/promise-chaining

Question 33

JS: if you do this, the .then functions will run

let myPromise = new Promise(function(resolve, reject) {
  setTimeout(() => resolve(1), 1000);
});

myPromise.then(function(result) {
alert(result); // 1
return result * 2;
});

myPromise.then(function(result) {
alert(result); // 1
return result * 2;
});

myPromise.then(function(result) {
alert(result); // 1
return result * 2;
});

Answer 33

all together when resolve() is called in the promise

Question 34

JS: to loop through the values of an object, type

{name: ‘string’, name: ‘string’}

Answer 34

let obj = {name: ‘string’, name: ‘string’}

for (const key in obj) {
console.log(obj[key])
}

or better

for (const key in obj) {
    if (obj.hasOwnProperty(key)) {
        console.log(obj[key]);
    }
}

Question 35

JS: to loop through the items of an array, type

Answer 35

let obj = [1, 2, 3]

for (const item of obj) {
console.log(item)
}

note: using for..in loops through the indexes

Question 36

JS: When you instantiate a promise, even into a variable,

Answer 36

it starts running immediately.

note, the promise methods are .then and .catch

Question 37

JS: setTimeout() can take an optional third argument which is

Answer 37

the value to be passed into the function

i.e.

var myPromise = new Promise(function(resolve, reject) {
    setTimeout(resolve, 500, 'string');
});

Question 38

JS: Promise.race([myPromise1, myPromise2]) passes into the .then() the

Answer 38

resolve value of the first promise to resolve.

Question 39

JS: Promise.all([myPromise1, myPromise2]) passes into the .then()

Answer 39

an array with all the resolve values.

Question 40

JS: The difference between == and === is

Answer 40

== is type converting equality and === is strict equality

Null==Undefined is true
Null===Undefined is false
‘5’ == 5 is true
‘5’ === 5 is false

Question 41

python: The namespace is

Answer 41

the dictionary that holds all the accessible environment variables names and values

Question 42

JS: Prototypal inheritance is

Answer 42

when you create a new function, it inherits properties and methods from its prototype which is called function, and that inherits from its prototype that is called object. When you call a property or method it looks up the prototype chain to find a property or method with that name.

You can add a function to a constructor function by typing
ConstructorFunctionName.prototype.newFuncName = function() {…}

Question 43

python: To create a virtual environment, type

Answer 43

python3 -m venv /path/

cd /path/
source bin/activate

and to close it
source bin/activate

Question 44

python: the difference between pass and continue is

Answer 44

continue forces the loop to skip to next iteration and pass does nothing.

Question 45

Python: To insert a list into the middle of another list, type

Answer 45

list_1.insert(4, list_2)

The 4 denotes the index to insert at

Question 46

Python: To remove one item from a list by its index, type

Answer 46

del my_list[2]

Question 47

Python: To slice a list or string by returning steps that skip, type

Answer 47

my_list[1::2], Add an extra colon

Question 48

Python: To return a string or list backwards using slice, type

Answer 48

my_string[::-1], make the skipping step a negative, and swap the start and end range [10:1:-1]

Question 49

Python: The difference between find and index is

Answer 49

str.find returns -1 when it does not find the substring.

While str.index raises ValueError:

Question 50

Python: To return a tuple with the index and value from an iterable, type

Answer 50

enumerate(my_iterable)

Question 51

Python: To apply a predefined function to every item in a list, in a short way, type

Answer 51

map(my_function, my_list)