問題描述
我有一個如下所示的數據框:
I have a dataframe like the one displayed below:
# Create an example dataframe about a fictional army
raw_data = {'regiment': ['Nighthawks', 'Nighthawks', 'Nighthawks', 'Nighthawks'],
'company': ['1st', '1st', '2nd', '2nd'],
'deaths': ['kkk', 52, '25', 616],
'battles': [5, '42', 2, 2],
'size': ['l', 'll', 'l', 'm']}
df = pd.DataFrame(raw_data, columns = ['regiment', 'company', 'deaths', 'battles', 'size'])
我的目標是將數據框中的每個字符串都轉換為大寫，使其看起來像這樣:
My goal is to transform every single string inside of the dataframe to upper case so that it looks like this:
注意:所有數據類型均為對象，不得更改；輸出必須包含所有對象.我想避免將每一列一一轉換...我想一般在整個數據幀上進行.
Notice: all data types are objects and must not be changed; the output must contain all objects. I want to avoid to convert every single column one by one... I would like to do it generally over the whole dataframe possibly.
到目前為止我嘗試的是這樣做但沒有成功
What I tried so far is to do this but without success
df.str.upper()
推薦答案
astype() 會將每個系列轉換為 dtype 對象(字符串)，然后調用 str() 方法在轉換后的系列上從字面上獲取字符串并調用函數 upper() 就可以了.請注意，在此之后，所有列的 dtype 都會更改為 object.
astype() will cast each series to the dtype object (string) and then call the str() method on the converted series to get the string literally and call the function upper() on it. Note that after this, the dtype of all columns changes to object.
In [17]: df
Out[17]:
regiment company deaths battles size
0 Nighthawks 1st kkk 5 l
1 Nighthawks 1st 52 42 ll
2 Nighthawks 2nd 25 2 l
3 Nighthawks 2nd 616 2 m
In [18]: df.apply(lambda x: x.astype(str).str.upper())
Out[18]:
regiment company deaths battles size
0 NIGHTHAWKS 1ST KKK 5 L
1 NIGHTHAWKS 1ST 52 42 LL
2 NIGHTHAWKS 2ND 25 2 L
3 NIGHTHAWKS 2ND 616 2 M
您可以稍后使用 to_numeric():
In [42]: df2 = df.apply(lambda x: x.astype(str).str.upper())
In [43]: df2['battles'] = pd.to_numeric(df2['battles'])
In [44]: df2
Out[44]:
regiment company deaths battles size
0 NIGHTHAWKS 1ST KKK 5 L
1 NIGHTHAWKS 1ST 52 42 LL
2 NIGHTHAWKS 2ND 25 2 L
3 NIGHTHAWKS 2ND 616 2 M
In [45]: df2.dtypes
Out[45]:
regiment object
company object
deaths object
battles int64
size object
dtype: object
這篇關于使用 Pandas 將整個數據幀從小寫轉換為大寫的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！