====== 大文字小文字変換(capitalize, upper, lower) ======

===== capitalize, upper, lower =====
<code python>
capitalize()
upper()
lower()
</code>

<code python>
str = 'this is a pen.'

str.capitalize()
'This is a pen.'

str = 'This is a pen.'

str.upper()
'THIS IS A PEN.'

str.lower()
'this is a pen.'
</code>

===== 参考文献 =====
[[https://docs.python.org/ja/3/library/stdtypes.html|組み込み型 — Python 3.7.3 ドキュメント]]\\