pandas 如何删除数据框列中的字符串子串？
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How to Remove a Substring of String in a Dataframe Column?
提问by MEhsan
I have this simplified dataframe:
我有这个简化的数据框：
ID, Date
1 8/24/1995
2 8/1/1899 :00
How can I use the power of pandas to recognize any date in the dataframe which has extra :00and removes it.
我怎样才能使用Pandas的力量来识别数据框中的任何日期，它有额外的:00并删除它。
Any idea how to solve this problem?
知道如何解决这个问题吗？
I have tried this syntax but did not help:
我试过这种语法但没有帮助：
df[df["Date"].str.replace(to_replace="\s:00", value="")]
The Output Should Be Like:
输出应该是这样的：
ID, Date
1 8/24/1995
2 8/1/1899
回答by Psidom
You need to assign the trimmed column back to the original column instead of doing subsetting, and also the str.replacemethod doesn't seem to have the to_replaceand valueparameter. It has patand replparameter instead:
您需要将修剪后的列分配回原始列而不是进行子集化，而且该str.replace方法似乎没有to_replaceandvalue参数。它具有pat和repl参数：
df["Date"] = df["Date"].str.replace("\s:00", "")
df
# ID Date
#0 1 8/24/1995
#1 2 8/1/1899
回答by piRSquared
To apply this to an entire dataframe, I'd stackthen unstack
要将其应用于整个数据帧，stack然后我会unstack
df.stack().str.replace(r'\s:00', '').unstack()
functionalized
功能化
def dfreplace(df, *args, **kwargs):
s = pd.Series(df.values.flatten())
s = s.str.replace(*args, **kwargs)
return pd.DataFrame(s.values.reshape(df.shape), df.index, df.columns)
Examples
例子
df = pd.DataFrame(['8/24/1995', '8/1/1899 :00'], pd.Index([1, 2], name='ID'), ['Date'])
dfreplace(df, '\s:00', '')
rng = range(5)
df2 = pd.concat([pd.concat([df for _ in rng]) for _ in rng], axis=1)
df2
dfreplace(df2, '\s:00', '')
