Python 如何获取pandas数据帧中单元格值的长度？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/37335598/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to get the length of a cell value in pandas dataframe?
提问by Kevin
Have a pandas dataframe:
有一个熊猫数据框：
idx Event
0 abc/def
1 abc
2 abc/def/hij
Run: df['EventItem'] = df['Event'].str.split("/")
跑： df['EventItem'] = df['Event'].str.split("/")
Got:
得到了：
idx EventItem
0 ['abc','def']
1 ['abc']
2 ['abc','def','hij']
Want to get the length of each cell, run df['EventCount'] = len(df['EventItem'])
想要得到每个的长度cell，运行df['EventCount'] = len(df['EventItem'])
Got:
得到了：
idx EventCount
0 6
1 6
2 6
How can I get the correct count as follow?
我怎样才能得到正确的计数如下？
idx EventCount
0 2
1 1
2 3
回答by root
You can use .str.lento get the length of a list, even though lists aren't strings:
您可以使用.str.len获取列表的长度，即使列表不是字符串：
df['EventCount'] = df['Event'].str.split("/").str.len()
Alternatively, the count you're looking for is just 1 more than the count of "/"'s in the string, so you could add 1 to the result of .str.count:
或者，您要查找的计数仅比"/"字符串中' 的计数多 1 ，因此您可以将 1 添加到 的结果中.str.count：
df['EventCount'] = df['Event'].str.count("/") + 1
The resulting output for either method:
任一方法的结果输出：
Event EventCount
0 abc/def 2
1 abc 1
2 abc/def/hij 3
Timings on a slightly larger DataFrame:
稍大的 DataFrame 上的计时：
%timeit df['Event'].str.count("/") + 1
100 loops, best of 3: 3.18 ms per loop
%timeit df['Event'].str.split("/").str.len()
100 loops, best of 3: 4.28 ms per loop
%timeit df['Event'].str.split("/").apply(len)
100 loops, best of 3: 4.08 ms per loop
回答by johnchase
You can use applyto apply the lenfunction to each column:
您可以使用apply将len函数应用于每一列：
df['EventItem'].apply(len)
0 2
1 1
2 3
Name: EventItem, dtype: int64
