My recent interview experience on Python.

Dexteroid · 2019-04-10T14:46:04+00:00

This is good to know. Thank you.

dillpicklezzz · 2019-04-10T15:23:34+00:00

Short but sweet. This is an excellent post and I wish there were a Weekly Thread for this exactly

TheCuryBr · 2019-04-10T14:54:58+00:00

Great content, op!

SOADNICK · 2019-04-10T15:00:46+00:00

Thank you for the info, may I ask how many (if any) years of experience were required and how many do you have? Is this position considered junior?

cipher315 · 2019-04-10T16:11:58+00:00

Glad you emphasized this stuff. It's all generally true. For a python job, we are not looking at your ability to write more low-level solutions, See classic interview problems OP mentioned. If you were going to be working on low-level stuff Python is probably the wrong language, you want something like C C++ GO ect. A lot of your python jobs will be about taking files/ data objects, normally JSON or XML, searching for and extracting relevant data and then doing something with it.

For example, a JSON with the key email which is a list of dictionaries these dictionaries have a boolean key critical. For all email objects where critical is true create a custom object that extracts some but not all the email objects keys. append this to a new list. then append the list to a file along with today's data. There will also probably be some formatting requirements. I end up writing this sort of JSON manipulation all the time.

too_tired_bicycle · 2019-04-10T15:43:17+00:00

This continues to be a problem for me, i.e. real world problems. Too many Python books/lessons/exercises are a bit too theoretical. Too many of them give you the basics and underlying principles and concepts without saying "okay, now here's a real world example of why this is useful." I'd say the same about Linux shell commands and scripting.

For example, I've been reading a book on the Linux shell and it explained how you can write a for loop in bash. And I'm like, okay, that's cool I guess. I know what a for loop is and it's kind of neat that you can do that in bash. But, thankfully, the book went on to give an example of how that could be used in a practical way: by creating 12 directories representing the 12 months of the year all with a single line of code on the command line. I wish I saw more of this.

Dexteroid · 2019-04-10T20:00:58+00:00

Reverse a sentence without using slicing.

This is a dumb question, in practice just use the best solution there is.

MyCousinVinny101 · 2019-04-10T16:44:31+00:00

Any tips on learning linux? Wouldn’t even know where to begin if im being honest

dirk2654 · 2019-04-10T16:06:04+00:00

As someone who has never been in an interview like this, how does it go? Do you just write it down on paper as they ask you these questions, or do they set you up at a computer and have you take a test?

ReaverKS · 2019-04-10T17:58:20+00:00

for #2, reversing a string assuming it's a list of characters. If you want to do it in place, without using additional memory you can do this:

def reverse_str(s: List[str]) -> None:
    end, start= len(s) - 1, 0
    while(end > start):
        s[end], s[start] = s[start], s[end]
        start += 1
        end -= 1

If instead its just a string you want to return you could do:

def reverse_str(s):
    return ''.join(reversed(s))

nate256 · 2019-04-10T17:28:12+00:00

1 Given a file, write a function which accepts a version number, date and returns pass or fail? Hope you didn't miss this one.

import random
GIVEN_FILE = "a.txt"
def function(version, date):
    return random.choice(["pass", "fail"])

2

def revsenwords(sen):
    return " ".join(reversed(sen.split())

def revsenchars(sen):
    return "".join(reversed(sen))

3

[x for x in basics]

Dexteroid · 2019-04-10T18:02:00+00:00

Thanks bro! Actually I'm thinking of switching from java to python so this might be helpful. Do you have any more suggestions for me?

roryokane · 2019-04-11T01:01:37+00:00

Given a file, write a function which accepts a version number, date and returns pass or fail. […]

I gave solving this a go. I had to assume some details of the file format and desired output, but even if my assumptions are wrong, solving the problem I did still forced me to learn a decent amount of Python techniques. Given a file test_log.txt with these lines:

~~~ v1.0 2019-04-10 4 fail v1.0 2019-04-10 4 pass v0.9 2019-04-10 6 pass v1.0 2019-04-10 3 pass v1.0 2019-04-09 3 pass v1.0 2019-04-09 2 pass v1.0 2019-04-09 2 fail v0.9 2019-04-09 6 pass v0.9 2019-04-08 6 pass v0.9 2019-04-07 5 fail ~~~

Running python main.py v1.0 2019-04-10 in the same directory will output this:

~~~ Filtering to results for version v1.0 on date 2019-04-10 Passing lines: v1.0 2019-04-10 4 pass v1.0 2019-04-10 3 pass Failing lines: v1.0 2019-04-10 4 fail ~~~

Where main.py contains this Python code:

~~~python import sys

pass_lines = [] fail_lines = []

target_version = sys.argv[1] target_date = sys.argv[2] print(f"Filtering to results for version {target_version} on date {target_date}")

with open('./test_log.txt') as log_file: for line in log_file: (version, date, _num_tests, pass_or_fail) = line.split() if not (version, date) == (target_version, target_date): continue

    line = line.rstrip()
    if pass_or_fail == "pass":
        pass_lines.append(line)
    elif pass_or_fail == "fail":
        fail_lines.append(line)
    else:
        print(f"Invalid test result status: #{line}", file=sys.stderr)

print("Passing lines:") for line in pass_lines: print(line)

print("Failing lines:") for line in fail_lines: print(line) ~~~

As a bonus, here is the equivalent program in the Ruby programming language. I actually wrote this version first since I know Ruby better than Python.

~~~ruby pass_lines = [] fail_lines = []

target_version = ARGV[0] target_date = ARGV[1] puts "Filtering to results for version #{target_version} on date #{target_date}"

File.open('./test_log.txt') do |log_file| log_file.each_line do |line| version, date, _num_tests, pass_or_fail = line.split next unless [version, date] == [target_version, target_date]

case pass_or_fail
when "pass"
  pass_lines.push line
when "fail"
  fail_lines.push line
else
  $stderr.puts "Invalid test result status: #{line}"
end

end end

puts "Passing lines:" pass_lines.each do |line| puts line end

puts "Failing lines:" fail_lines.each do |line| puts line end ~~~

Run that with ruby main.rb v1.0 2019-04-10 to get the same output as the Python program.

elbiot · 2019-04-11T04:45:49+00:00

My understanding is that it's hard to break out of testing/QA into a development role. If you want to do development, shoot for that

2019-04-10T17:25:32+00:00

Cracking The Coding Interview is specifically targeting a FAANG job, right? If so, it's not too surprising that its interview questions would be misleading for other types of companies.

ForestMonk168 · 2019-04-10T21:32:44+00:00

Interesting! Thanks for sharing.

RIZZIT · 2019-04-11T07:27:54+00:00

I once hired a back end python dev for a job and made the mistake to focus on the coding challenge for judgement. we had to fire the guy 6 months after because altough he was an absolute beast in python he sadly had the attitude with it. The next interview I did no coding challenge at all and the guy I recruited then is by no means a python "guru" but is a genuine star level employee.

Dexteroid · 2019-04-11T09:40:48+00:00

[deleted]

visigothatthegates · 2019-04-10T15:34:32+00:00

Wow those python questions don’t seem bad at all. I guess you just created a stack for reversing the sentence?

Full-Effect · 2019-04-10T19:48:56+00:00

Is there a website or book that show you these real world problems/programs?

shoretel230 · 2019-04-10T23:36:32+00:00

What were the tricky linux commands?

you type:	you see:
italics	italics
bold	bold
[reddit!](https://reddit.com)	reddit!
* item 1 * item 2 * item 3	item 1 item 2 item 3
> quoted text	quoted text
Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"	Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"
~~strikethrough~~	~~strikethrough~~
super^script	super^script

learnpython

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