如何在Python中将过滤后的字符串附加到新列表中？

我想在从旧列表中筛选出来的新列表中附加一个字符串

到目前为止，我所尝试的：

languages = ['thai01', 'thai02', 'thai03', 'jap01', 'jap02', 'jap03']

thai = []
japanese = []


def filter_str(lang):
    if 'tha' in lang:
        return True
    else:
        return False


filter_lang = filter(filter_str, languages)
thai = thai.append(filter_lang)

print(thai)

我的预期产出是：

['thai01', 'thai02', 'thai03']

---

您可以使用列表：

languages = ['thai01', 'thai02', 'thai03', 'jap01', 'jap02', 'jap03']
thai = [x for x in languages if 'thai' in x]
print(thai)

产出：

['thai01', 'thai02', 'thai03']

要帮助您理解此oneliner的逻辑，请参阅以下基于代码的示例：

languages = ['thai01', 'thai02', 'thai03', 'jap01', 'jap02', 'jap03']

thai = []

def filter_str(lang):
    if 'tha' in lang:
        return True
    else:
        return False

for x in languages:
    if filter_str(x):
        thai.append(x)

print(thai)
# ['thai01', 'thai02', 'thai03']

检查字符串

'tha'

是否发生的

for

循环（在本例中，借助于函数），与上面的列表理解逻辑相同（尽管在第一个示例中，您甚至不需要函数）。您还可以将列表理解与功能结合使用：

languages = ['thai01', 'thai02', 'thai03', 'jap01', 'jap02', 'jap03']

def filter_str(lang):
    if 'tha' in lang:
        return True
    else:
        return False

thai = [x for x in languages if filter_str(x)]

print(thai)
# ['thai01', 'thai02', 'thai03']

---

执行下一步操作，而不是使用泰国语。追加：

thai.extend（过滤器（过滤器，语言））

• 如果字符串以指定的前缀（字符串）开头，则方法返回True。如果不是，则返回False

Ex.

languages = ['thai01', 'thai02', 'thai03', 'jap01', 'jap02', 'jap03']

thai = []
japanese = []

for x in languages:
    if x.startswith("tha"):
        thai.append(x)
    else:
        japanese.append(x)
print(thai)
print(japanese)

O/p:

['thai01', 'thai02', 'thai03']
['jap01', 'jap02', 'jap03']

---

为什么不做一个理解？e、 g

thai = [x for x in languages if filter_str(x)]

---

您还可以将

过滤器

与lambda函数一起使用

languages = ['thai01', 'thai02', 'thai03', 'jap01', 'jap02', 'jap03']
thai = list(filter(filter_str,languages))  # or  thai = list(filter(lambda x:'thai' in x,languages))

print(thai)    #['thai01', 'thai02', 'thai03']

或列表理解

thai = [y for y in languages if 'tha' in y]

---

如果您喜欢功能性风格，可以使用：

---

谢谢，我对列表理解有了更多的了解。

from operator import methodcaller

languages = ['thai01', 'thai02', 'thai03', 'jap01', 'jap02', 'jap03']
thai = list(filter(methodcaller('startswith', 'tha'), languages))