python

• start http server: python3 -m http.server

• install requirements.txt: python3 -m pip install -r <path_to_requirements>

• create requirements.txt: pip freeze > requirements.txt

• uninstall packages: pip uninstall -r requirements.txt -y

• iPython:

  • turn on module autoreload:

    %load_ext autoreload
    %autoreload 2
    

• read csv:

import csv

with open('employee_birthday.txt') as csv_file:
    csv_reader = csv.reader(csv_file, delimiter=',')
    line_count = 0
    for row in csv_reader:
        if line_count == 0:
            print(f'Column names are {", ".join(row)}')
            line_count += 1
        else:
            print(f'\t{row[0]} works in the {row[1]} department, and was born in {row[2]}.')
            line_count += 1
    print(f'Processed {line_count} lines.')

• read file:

with open('readme.txt') as f:
    lines = f.readlines()

json files

• read json file:

import json

with open('json_data.json') as json_file:
    data = json.load(json_file)
    print(data)

• write json file:

with open('json_data.json', 'w') as outfile:
    json.dump(json_string, outfile)

Debug

Basic navigation

Command	Aliases	What it does
h	help	General help or help <cmd>.
q	quit, exit	Quit debugger and program.
c	continue	Run until next breakpoint or program end.
n	next	Step over the current line (stay in frame).
s	step	Step into calls.
r	return	Run until current function returns.
unt	until	Continue to a later line in the current frame; until <lineno> to a specific line.
j <lineno>	jump	Set next line to execute (no running of skipped code).
run	restart	Restart the program.

Breakpoint

Command	What it does
b	List breakpoints.
b <lineno>	Breakpoint at line in current file.
b <file>:<lineno>	Breakpoint in another file.
b <funcname>	Breakpoint at function entry.
tbreak <...>	Temporary breakpoint (auto-clears when hit).
condition <bpnum> <expr>	Make breakpoint conditional.
ignore <bpnum> <count>	Ignore breakpoint the next N times.
disable <bpnum> / enable <bpnum>	Disable/enable a breakpoint.
cl	Clear all breakpoints.
cl <bpnum>	Clear one breakpoint.

Inspection

Command	Alias	Description
l	list	Show source code around the current line.
l <start>,<end>	—	List source lines in a range.
w	where	Print stack trace (where you are).
u	up	Move up one stack frame.
d	down	Move down one stack frame.
p <expr>	print	Evaluate and print expression.
pp <expr>	—	Pretty-print expression.
a	args	Show arguments of the current function.
retval	—	Show the return value of the last function.