Python strings [miguel angel torres egea]

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= Python strings
{{tag>python}}
== comp
  * Exact match (equality comparison): ==, !=
  * Partial match: in, not in
  * Forward/backward match: startswith(), endswith()
  * Order comparison: <, <=, >, >=
  * Case-insensitive comparison: upper(), lower()
  * Regex: re.search(), re.fullmatch()
/via: [[https://note.nkmk.me/en/python-str-compare/]]

== string formatting
  * string formating[[https://realpython.com/python-string-formatting/]]
    * ''"string%s"%(param1)''
    * ''"string {} {}".format(1parm,2param)''
    * ''"string {1}{2}{1}".format(1param,2param)''
    * interpolación (f-string): ''f"string {name} {a + b}"''
    * Template strings

== f-strings (Literal String Interpolation)
  * To create an f-string, prefix the string with the letter “ f ”. The string itself can be formatted in much the same way that you would with str.format(). F-strings provide a concise and convenient way to embed python expressions inside string literals for formatting.
  * F-strings are faster than the two most commonly used string formatting mechanisms, which are % formatting and str.format().
<code python>
val = 'Geeks'
print(f"{val}for{val} is a portal for {val}.")
</code>
<code python>
import datetime
 
today = datetime.datetime.today()
print(f"{today:%B %d, %Y}")
</code>
Backslash Cannot be used in format string directly.
<code python error>
f"newline: {ord('\n')}"
</code>
<code python correcto>
newline = ord('\n')
 
print(f"newline: {newline}")
</code>
/+info: [[https://www.python.org/dev/peps/pep-0498/]]
/via: [[https://www.geeksforgeeks.org/formatted-string-literals-f-strings-python/]]

== string fill
  * ''ljust()'', ''rjust()'', ''center()''
  * ''%15s'', ''%15-s''
  * ''{:15}'', ''{:>15}''
/via:[[https://www.delftstack.com/es/howto/python/python-pad-string-with-spaces/]]
  * ''zfill()''

== zero fill
  * ''n=42''
  * ''print(f'{n:05d}')''
  * ''print('%05d' % n)''
  * ''print('{0:05d}'.format(n))''
  * 00042
 /via: [[https://www.python-engineer.com/posts/pad-zeros-string/]]
== concatenate
  * ''s1+s2''
  * ''"%s %s"%(s1,s2)''
  * ''"-".join([s1,s2])''
  * ''"{}{}".format(s1,s2)''

/via: [[https://www.tutorialspoint.com/how-to-concatenate-two-strings-in-python]]