append 或将一个 dataframe 中的值连接到另一个 Z6A8064B5DF4794555500553C47C55057DZ 中的 Z251D2CEBBFE303B95E4AZDC1 中的每一行

Question

I'm normally OK on the joining and appending front, but this one has got me stumped.

I've got one dataframe with only one row in it. I have another with multiple rows. I want to append the value from one of the columns of my first dataframe to every row of my second.

df1:

id	Value
1	word

df2:

id	data
1	a
2	b
3	c

Output I'm seeking:

df2

id	data	Value
1	a	word
2	b	word
3	c	word

I figured that this was along the right lines, but it listed out NaN for all rows:

df2 = df2.append(df1[df1['Value'] == 1])

I guess I could just join on the id value and then copy the value to all rows, but I assumed there was a cleaner way to do this.

Thanks in advance for any help you can provide!

Answer 1

Just get the first element in the value column of df1 and assign it to value column of df2

df2['value'] = df1.loc[0, 'value']