プログラミング

リストの要素を削除

2017年11月20日 by 河副太智 Leave a Comment

<span class="cm-variable">alphabet</span> = [<span class="cm-string">"a"</span>, <span class="cm-string">"b"</span>, <span class="cm-string">"c"</span>, <span class="cm-string">"d"</span>, <span class="cm-string">"e"</span>]
<span class="cm-keyword">del</span>(<span class="cm-variable">alphabet</span>[<span class="cm-number">3</span>:])
<span class="cm-keyword">del</span>(<span class="cm-variable">alphabet</span>[<span class="cm-number">0</span></code><code class="cm-s-ipython language-python">])</code><code class="cm-s-ipython language-python">
<span class="cm-builtin">print</span>(<span class="cm-variable">alphabet</span>)  <span class="cm-comment"># ["b", "c"]が出力される

</span>

alphabet = ["a", "b", "c", "d", "e"]

del(alphabet[3:])

del(alphabet[0</code><code class="cm-s-ipython language-python">])</code><code class="cm-s-ipython language-python">

print(alphabet) # ["b", "c"]が出力される

del(リスト[インデックス番号])

例

In [9]: sample_list = ['a','b','c','d','e']

In [10]: sample_list[0]
Out[10]: 'a'

In [11]: sample_list[0:]
Out[11]: ['a', 'b', 'c', 'd', 'e']

In [12]: sample_list[0:-1]
Out[12]: ['a', 'b', 'c', 'd']

In [13]: sample_list[0:4]
Out[13]: ['a', 'b', 'c', 'd']

In [19]: sample_list[-3:]
Out[19]: ['c', 'd', 'e']

In [22]: sample_list[-3:-1]
Out[22]: ['c', 'd']

# リストを反転させるとき
In [14]: sample_list[::-1]
Out[14]: ['e', 'd', 'c', 'b', 'a']

In [9]: sample_list = ['a','b','c','d','e']

In [10]: sample_list[0]

Out[10]: 'a'

In [11]: sample_list[0:]

Out[11]: ['a', 'b', 'c', 'd', 'e']

In [12]: sample_list[0:-1]

Out[12]: ['a', 'b', 'c', 'd']

In [13]: sample_list[0:4]

Out[13]: ['a', 'b', 'c', 'd']

In [19]: sample_list[-3:]

Out[19]: ['c', 'd', 'e']

In [22]: sample_list[-3:-1]

Out[22]: ['c', 'd']

# リストを反転させるとき

In [14]: sample_list[::-1]

Out[14]: ['e', 'd', 'c', 'b', 'a']

<span class="cm-variable">alphabet</span> = [<span class="cm-string">"a"</span>, <span class="cm-string">"b"</span>, <span class="cm-string">"c"</span>, <span class="cm-string">"d"</span>, <span class="cm-string">"e"</span>]
<span class="cm-variable">alphabet</span>[<span class="cm-number">0</span>] = <span class="cm-string">"A"</span>
<span class="cm-variable">alphabet</span>[<span class="cm-number">1</span>:<span class="cm-number">3</span>] = [<span class="cm-string">"B"</span>, <span class="cm-string">"C"</span>]
</code><code class="cm-s-ipython language-python"><span class="cm-builtin">print</span></code><code class="cm-s-ipython language-python">(<span class="cm-variable">alphabet</span>)  </code><code class="cm-s-ipython language-python"><span class="cm-comment"># ["A", "B", "C", "d", "e"]が出力される</span></code><code class="cm-s-ipython language-python">

<span class="cm-variable">alphabet</span> = <span class="cm-variable">alphabet</span> <span class="cm-operator">+</span> [<span class="cm-string">"f"</span>]
<span class="cm-variable">alphabet</span> += [<span class="cm-string">"g"</span>,<span class="cm-string">"h"</span>]
<span class="cm-variable">alphabet</span>.<span class="cm-property">append</span>(<span class="cm-string">"i"</span>)
<span class="cm-builtin">print</span>(<span class="cm-variable">alphabet</span>) <span class="cm-comment"># ["A", "B", "C", "d", "e", "f", "g", "h", "i"]が出力される</span>

alphabet[0] = "A"

alphabet[1:3] = ["B", "C"]

</code><code class="cm-s-ipython language-python">print</code><code class="cm-s-ipython language-python">(alphabet) </code><code class="cm-s-ipython language-python"># ["A", "B", "C", "d", "e"]が出力される</code><code class="cm-s-ipython language-python">

alphabet = alphabet + ["f"]

alphabet += ["g","h"]

alphabet.append("i")

print(alphabet) # ["A", "B", "C", "d", "e", "f", "g", "h", "i"]が出力される

pass とcontinueの違い　ifを抜ける

2017年10月30日 by 河副太智 Leave a Comment

passだとifを抜ける
continueだとifの中のelifも実行される。

■continueの場合以下のelifは実行される

if len(ans) != 6:
continue(elifは実行される)
elif ans.isdecimal() == False:
print "a"

if len(ans) != 6:

continue(elifは実行される)

elif ans.isdecimal() == False:

print "a"

■passの場合以下のelifは実行されない

if len(ans) != 6:
pass (elifは実行されない)
elif ans != c[0]:
print "a"

if len(ans) != 6:

pass (elifは実行されない)

elif ans != c[0]:

print "a"

# 半角数字
print("1".isdigit()) # True
print("1".isdecimal()) # True
print("1".isnumeric()) # True
# 半角数値(符号付き)
print("0.01".isdigit()) # False 
print("0.01".isdecimal()) # False 
print("0.01".isnumeric()) # False 
 
# 半角数値(小数)
print("0.01".isdigit()) # False 
print("0.01".isdecimal()) # False 
print("0.01".isnumeric()) # False 
# U+0660を含む場合
print("0٠01".isdigit()) # True 
print("0٠01".isdecimal()) # True 
print("0٠01".isnumeric()) # True 
# 全角数字
print("１".isdigit()) # True
print("１".isdecimal()) # True
print("１".isnumeric()) # True
# 全角漢数字
print("百".isdigit()) # False 
print("百".isdecimal()) #  False
print("百".isnumeric()) # True
# 全角ローマ数字
print("Ⅳ".isdigit()) # False 
print("Ⅳ".isdecimal()) # False 
print("Ⅳ".isnumeric()) # True

リストの要素を削除

リスト

pass とcontinueの違い　ifを抜ける

変数が空かどうかを確認

HTMLヘッダー

文字列の数値判定