Python 条件 If 语句：如果行中的值包含字符串...设置另一列等于字符串
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Conditional If Statement: If value in row contains string ... set another column equal to string
提问by PineNuts0
EDIT MADE:
编辑制作：
I have the 'Activity' column filled with strings and I want to derive the values in the 'Activity_2' column using an if statement.
我有一个充满字符串的“Activity”列，我想使用 if 语句导出“Activity_2”列中的值。
So Activity_2 shows the desired result. Essentially I want to call out what type of activity is occurring.
因此 Activity_2 显示了所需的结果。本质上，我想指出正在发生的活动类型。
I tried to do this using my code below but it won't run (please see screen shot below for error). Any help is greatly appreciated!
我尝试使用下面的代码执行此操作，但它无法运行（有关错误，请参阅下面的屏幕截图）。任何帮助是极大的赞赏！
for i in df2['Activity']:
if i contains 'email':
df2['Activity_2'] = 'email'
elif i contains 'conference'
df2['Activity_2'] = 'conference'
elif i contains 'call'
df2['Activity_2'] = 'call'
else:
df2['Activity_2'] = 'task'
Error: if i contains 'email':
^
SyntaxError: invalid syntax
采纳答案by DovaX
The current solution behaves wrongly if your df contains NaN values. In that case I recommend using the following code which worked for me
如果您的 df 包含 NaN 值，则当前解决方案的行为是错误的。在这种情况下，我建议使用以下对我有用的代码
temp=df.Activity.fillna("0")
df['Activity_2'] = pd.np.where(temp.str.contains("0"),"None",
pd.np.where(temp.str.contains("email"), "email",
pd.np.where(temp.str.contains("conference"), "conference",
pd.np.where(temp.str.contains("call"), "call", "task"))))
回答by Psidom
I assume you are using pandas, then you can use numpy.where, which is a vectorized version of if/else, with the condition constructed by str.contains:
我假设您正在使用pandas，那么您可以使用numpy.where，它是if/else的矢量化版本，条件由str.contains：
df['Activity_2'] = pd.np.where(df.Activity.str.contains("email"), "email",
pd.np.where(df.Activity.str.contains("conference"), "conference",
pd.np.where(df.Activity.str.contains("call"), "call", "task")))
df
# Activity Activity_2
#0 email personA email
#1 attend conference conference
#2 send email email
#3 call Sam call
#4 random text task
#5 random text task
#6 lwantto call call
回答by moshfiqur
This also works:
这也有效：
df.loc[df['Activity'].str.contains('email'), 'Activity_2'] = 'email'
df.loc[df['Activity'].str.contains('conference'), 'Activity_2'] = 'conference'
df.loc[df['Activity'].str.contains('call'), 'Activity_2'] = 'call'
回答by Prakash Palnati
you have an invalid syntax for checking strings.
检查字符串的语法无效。
try using
尝试使用
for i in df2['Activity']:
if 'email' in i :
df2['Activity_2'] = 'email'
