Links: PYTHON - PROGRAMMING
Rel: python standard library; regular_expressions
Ref:
Tags: #public

---

import re

---

re.search() -> None if not found
re.findall() -> [] if not found

if using a single group (), returns that group in a list only
if using multiple groups, return each group item in a tuple

example.txt

This is a text file.
It can be read by the os through

with open(os.path.join(path, filename) as f:
print(f.read)

...

re **.compile()** -> matches
```py
import re

sentence = 'Start a sentence and then bring it to an end'
pattern = re.compile('sentence')
matches = pattern.search(sentence)
print(matches)
# <re.Match object; span=(8, 16), match='sentence'> {: id="<re.match-object;-span=(8,-16),-match='sentence'>" }

re.sub(p, repl, line)
replaces all instances of found pattern p with a string (line)

change contents of a line :

```py # foo.txt {: id="foo.txt" }
ignored

regexd

alsoig

heres more lines

thar be a line

import re

with open('foo.txt', 'r') as read_file:
out_file = open('bar.txt', 'w')
for line in read_file.readlines():
line = re.sub(r'regexd', 'this line was changed', line)
out_file.write(line)

``` # bar.txt {: id="bar.txt" }
ignored

this line was changed

alsoig

heres more lines

thar be a line

re .findall()

ex_str = """
Bill is 99 years old, and Chris is 56 years old.
Abe is 97, and his grandfather, Tim is 87.
"""

>>> ages = re.findall(r'\d{1,3}', ex_str)
>>> print(ages)
['99', '56', '97', '87']

>>> names = re.findall(r'[A-Z][a-z]*', exampleString)
>>> # starts at anything A-Z -> then anything 0 or more a-z, but as soon as a whitespace, period, comma, etc. -> will stop parce {: id="starts-at-anything-a-z-->-then-anything-0-or-more-a-z,-but-as-soon-as-a-whitespace,-period,-comma,-etc.-->-will-stop-parce" }
>>> 
>>> print(names)
['Bill', 'Chris', 'Abe', 'Tim']

re .split()

>>> reg_str = "Hello, World"
>>> reg_splt = re.split(r'(,)', reg_str)
>>> print(reg_splt)
['Hello', ',', ' World']

---

tabbed lines

import re

NONTAB = r'^-(.*)'
TABBED = r'(\t)(.*)'

with open('tabbs.txt', 'r') as f:
    fi = f.readlines()
    for i, l in enumerate(fi):
        if re.match(NONTAB, l):
            print(i, 'nontabbed')
        if re.match(TABBED, l):
            print(i, 'tabbed')

``` # tabbs.txt {: id="tabbs.txt" }

• professional communication:
  — Be on time - if going to be late, contact the customer
  — Actively listening - allow to describe problem in great detail; take notes if necessary
  — Clarify customer statements - ask open ended questions to narrow scope of problems
  — Maintain positive attitude / project confidence
  — Use proper language and avoid jargon, acronyms, and slang
  — Set and meet expectations/timeline and communicate status with customer
  — Be culturally sensitive
  — Use appropriate professional titles
  — Avoid distractions when working with customers
  — Avoid being judgemental
  — Avoid dismissing customer problems
  — Deal appropriately with customers’ confidential and private materials
  — Don’t argue with customers or be defensive
  — Follow up with customer later to verify satisfaction
  — Provide proper documentation on services provided
  — Offer different repair/replacement options

--- 
e.g.
#### simpletool.to_seconds() {: id="simpletool.to-seconds()" }

```py
import re


def to_seconds(timestr):
    """
    :param timestr: e.g. '1d3h27m54s'
    """
    reg = r'(\d+)?d?(\d+)?h?(\d+)?m?(\d+)s'
    to_s = [86400, 3600, 60, 1]

    if (m := re.match(reg, timestr).groups()):
        ts = [int(x) for x in m if x]
        to_s = to_s[-len(ts):]
        t = sum([n*to_s[i] for i,n in enumerate(ts)])
        return t


def to_seconds(timestr):

    reg = r'(\d+d)?(\d+h)?(\d+m)?(\d+d)?(\d+s)?'
    to_s = {'d': 86400, 'h': 3600, 'm': 60, 's': 1}

    if (m := re.match(reg, timestr).groups()):
        ts = {x[-1]:int(x[:-1]) for x in m if x}
        t = sum([to_s[k]*ts[k] for k in ts.keys()])
        return t



print(to_seconds('1d3h27m54s'))
print(to_seconds('3h54s'))
print(to_seconds('3h27m54s'))
print(to_seconds('1d'))

---

# re-write re.sub() with string indexing {: id="re-write-re.sub()-with-string-indexing" }
import re

s = 'this is my stringyyy here to fix' 
r = 'stringyyy'
m = re.search(r, s)
sx = s[:m.span()[0]] # 'this is my ' {: id="'this-is-my-'" }
sz = s[m.span()[1]:] # ' here to fix' {: id="'-here-to-fix'" }
sy = 'string'
sn = sx + sy + sz

print(sn)
print(re.sub(r, sy, s))

---

w/ f-strings :

>>> y = 'badgers'
>>> x = rf'^{y}'
>>> import re
>>> z = 'badgers are here'
>>> a = 'are badgers here'
>>> re.findall(x, z)
['badgers']
>>> re.findall(x, a)
[]