リストのスライス
l = [
{'reviewAverage': 3.6, 'reviewCount': 352},
{'reviewAverage': 2.4, 'reviewCount': 164},
{'reviewAverage': 1.9, 'reviewCount': 164},
{'reviewAverage': 4.2, 'reviewCount': 1257},
{'reviewAverage': 5.0, 'reviewCount': 29},
{'reviewAverage': 3.8, 'reviewCount': 874},
]
l = l[:3]
pprint.pprint(l)
# [{'reviewAverage': 3.6, 'reviewCount': 352},
# {'reviewAverage': 2.4, 'reviewCount': 164},
# {'reviewAverage': 1.9, 'reviewCount': 164}]
リストに要素を追加
l = ['A', 'B']
l.append('add')
print(l)
# ['A', 'B', 'add']
add = ['add']
l = ['A', 'B'] + add
print(l)
# ['A', 'B', 'add']
リスト内包表記
l = [1,2,3,4,5]
l_1 = []
for i in l:
l_1.append(str(i))
print(l_1)
# ['1', '2', '3', '4', '5']
# リスト内包表記
l_2 = [str(i) for i in l]
print(l_2)
# ['1', '2', '3', '4', '5']
配列にネストした配列を複数追加
parent = []
child_1 = [1, 2, 3]
child_2 = [4, 5, 6]
child_3 = [7, 8, 9]
parent.append(child_1)
parent.append(child_2)
parent.append(child_3)
print(parent)
# [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
parent = []
child_1 = [1, 2, 3]
child_2 = [4, 5, 6]
child_3 = [7, 8, 9]
parent += [child_1, child_2, child_3]
print(parent)
child_1 = [1, 2, 3]
child_2 = [4, 5, 6]
child_3 = [7, 8, 9]
parent = [child_1, child_2, child_3]
print(parent)
リストの先頭に要素を追加
val = [10, 'a']
add = 'add'
val.insert(0, add)
print(val)
# ['add', 10, 'a']
リストに空の要素を追加
l = ['S', 860, 'M', 950]
l += [''] * 6
print(l)
# ['S', 860, 'M', 950, '', '', '', '', '', '']
リスト同士の結合
list_merge = []
list1 = [1, 2, 3]
list2 = [4, 5, 6]
list_merge += list1
list_merge += list2
print(list_merge)
# [1, 2, 3, 4, 5, 6]
list_merge = [[1, 2, 3], [4, 5, 6]]
list_merge2 = []
for lst in list_merge:
for l in lst:
list_merge2.append(l)
print(list_merge2)
リストの中身の連結
文字列のリストを連結
l = ['aaa', 'bbb', 'ccc']
s = ''.join(l)
print(s)
# aaabbbccc
s = ','.join(l)
print(s)
# aaa,bbb,ccc
s = '-'.join(l)
print(s)
# aaa-bbb-ccc
s = '\n'.join(l)
print(s)
# aaa
# bbb
# ccc
数値のリストを文字列として連結
join()の引数に文字列以外を要素とするリストを指定するとエラーとなる。
l = [0, 1, 2]
s = '-'.join([str(n) for n in l])
print(s)
# 0-1-2
リストから重複した要素を削除
l = [3, 3, 2, 1, 5, 1, 4, 2, 3]
print(list(dict.fromkeys(l)))
# [3, 2, 1, 5, 4]
リストをソート
l = ['header.php', 'sidebar.php', 'content.php', 'modal.php', 'code.php']
l.sort()
print(l)
# ['code.php', 'content.php', 'header.php', 'modal.php', 'sidebar.php']
リストの中身に連番をふる
l_content = ['a', 'b', 'c', 'd', 'e']
countNum = 1
for l in l_content:
print(l + '-' + str(countNum))
countNum += 1
# a-1
# b-2
# c-3
# d-4
# e-5
l_content = ['a', 'b', 'c', 'd', 'e']
l_len = len(l_content)
print(l_len)
# 5
for lc, ll in zip(l_content, range(1, l_len + 1)):
print(lc + '-' + str(ll))
# a-1
# b-2
# c-3
# d-4
# e-5
リストから数値のみ取り出す
l = [1000, 'S', 860, 'M', 950]
s = []
for i in l:
if type(i) is int:
s.append(i)
print(s)
# [1000, 860, 950]
リストから最小値・最大値を取り出す
s = ['Z', 'A', 'B', 'C']
i = [1000, 860, 950]
min_s = min(s)
print(min_s)
# A
min_i = min(i)
print(min_i)
# 860
リスト内の要素の存在を判定 in / not in
l = [0, 1, 2]
i = 0
if i in l:
print('true')
l = [1,2,3,4,5,6,7,8,9]
a = [1,2,3]
b = [4, 5]
ab = a + b
print(ab)
# [1, 2, 3, 4, 5]
l2 = []
for n in l:
if n not in ab:
l2.append(n)
print(l2)
# [6, 7, 8, 9]
特定の文字列を含む配列の要素を抽出
l = ['aaa', 'bbbX', 'ccc', 'dddX']
elm_in = [s for s in l if 'X' in s]
print(elm_in)
# ['bbbX', 'dddX']
elm_not_in = [s for s in l if 'X' not in s]
print(elm_not_in)
# ['aaa', 'ccc']
リストの中身をランダムに取り出す
import random
l = ['a', 'b', 'c', 'd', 'e']
r = l[random.randrange(0, len(l), 1)]
print(r)
split() 文字列を分割してリスト化
s = 'one two three'
l = s.split()
print(l)
# ['one', 'two', 'three']
s = 'one two three'
l = s.split()
print(l)
# ['one', 'two', 'three']
s = 'one\ttwo\tthree'
l = s.split()
print(l)
# ['one', 'two', 'three']
リストを辞書に変換
l = ['JS', 'JavaScript']
d = {l[0]: l[1]}
print(d)
# {'JS': 'JavaScript'}
2つのリストを辞書に変換
l1 = ['a', 'b', 'c']
l2 = [1, 2, 3]
d = dict(zip(l1, l2))
print(d)
# {'a': 1, 'b': 2, 'c': 3}
リスト内の空の要素を除外する
l = [1, '', 3, '', 5]
l = [i for i in l if i != '']
print(l)
# [1, 3, 5]
多重配列の中身を順番に取り出す
- オブジェクトの型で判定する場合、
is 型 で判定できる
Pythonで型を取得・判定するtype関数, isinstance関数 | note.nkmk.me
l = [[1, 2, 3], 4, [5, 6]]
for i in l:
if type(i) is list:
for e in i:
print(e)
else:
print(i)
